+# Xous and Betrusted at FOSSASIA 2020
-A framework for easily creating beautiful presentations using HTML. [Check out the live demo](https://revealjs.com/).
-
-reveal.js comes with a broad range of features including [nested slides](https://github.com/hakimel/reveal.js#markup), [Markdown support](https://github.com/hakimel/reveal.js#markdown), [PDF export](https://github.com/hakimel/reveal.js#pdf-export), [speaker notes](https://github.com/hakimel/reveal.js#speaker-notes) and a [JavaScript API](https://github.com/hakimel/reveal.js#api). There's also a fully featured visual editor and platform for sharing reveal.js presentations at [slides.com](https://slides.com?ref=github).
-
-### Supporting reveal.js
-This project was started and is maintained by [@hakimel](https://github.com/hakimel/) with the help of many [contributions from the community](https://github.com/hakimel/reveal.js/graphs/contributors). The best way to support the project is to [become a paying member of Slides.com](https://slides.com/pricing)—the reveal.js presentation platform that Hakim is building.
-
-
-## Table of contents
-
-- [Online Editor](#online-editor)
-- [Installation](#installation)
- - [Basic setup](#basic-setup)
- - [Full setup](#full-setup)
- - [Folder Structure](#folder-structure)
-- [Instructions](#instructions)
- - [Markup](#markup)
- - [Markdown](#markdown)
- - [Element Attributes](#element-attributes)
- - [Slide Attributes](#slide-attributes)
-- [Configuration](#configuration)
-- [Presentation Size](#presentation-size)
-- [Dependencies](#dependencies)
-- [Ready Event](#ready-event)
-- [Auto-sliding](#auto-sliding)
-- [Keyboard Bindings](#keyboard-bindings)
-- [Vertical Slide Navigation](#vertical-slide-navigation)
-- [Touch Navigation](#touch-navigation)
-- [Lazy Loading](#lazy-loading)
-- [API](#api)
- - [Custom Key Bindings](#custom-key-bindings)
- - [Slide Changed Event](#slide-changed-event)
- - [Presentation State](#presentation-state)
- - [Slide States](#slide-states)
- - [Slide Backgrounds](#slide-backgrounds)
- - [Parallax Background](#parallax-background)
- - [Slide Transitions](#slide-transitions)
- - [Internal links](#internal-links)
- - [Fragments](#fragments)
- - [Fragment events](#fragment-events)
- - [Code syntax highlighting](#code-syntax-highlighting)
- - [Slide number](#slide-number)
- - [Overview mode](#overview-mode)
- - [Fullscreen mode](#fullscreen-mode)
- - [Embedded media](#embedded-media)
- - [Stretching elements](#stretching-elements)
- - [Resize Event](#resize-event)
- - [postMessage API](#postmessage-api)
-- [PDF Export](#pdf-export)
-- [Theming](#theming)
-- [Speaker Notes](#speaker-notes)
- - [Share and Print Speaker Notes](#share-and-print-speaker-notes)
- - [Server Side Speaker Notes](#server-side-speaker-notes)
-- [Plugins](#plugins)
-- [Multiplexing](#multiplexing)
- - [Master presentation](#master-presentation)
- - [Client presentation](#client-presentation)
- - [Socket.io server](#socketio-server)
-- [MathJax](#mathjax)
-- [License](#license)
-
-#### More reading
-
-- [Changelog](https://github.com/hakimel/reveal.js/releases): Up-to-date version history.
-- [Examples](https://github.com/hakimel/reveal.js/wiki/Example-Presentations): Presentations created with reveal.js, add your own!
-- [Browser Support](https://github.com/hakimel/reveal.js/wiki/Browser-Support): Explanation of browser support and fallbacks.
-- [Plugins](https://github.com/hakimel/reveal.js/wiki/Plugins,-Tools-and-Hardware): A list of plugins that can be used to extend reveal.js.
-
-
-## Online Editor
-
-Presentations are written using HTML or Markdown but there's also an online editor for those of you who prefer a graphical interface. Give it a try at [https://slides.com](https://slides.com?ref=github).
-
-
-## Installation
-
-The **basic setup** is for authoring presentations only. The **full setup** gives you access to all reveal.js features and plugins such as speaker notes as well as the development tasks needed to make changes to the source.
-
-### Basic setup
-
-The core of reveal.js is very easy to install. You'll simply need to download a copy of this repository and open the index.html file directly in your browser.
-
-1. Download the latest version of reveal.js from elements
- { src: 'plugin/highlight/highlight.js', async: true },
-
- // Zoom in and out with Alt+click
- { src: 'plugin/zoom-js/zoom.js', async: true },
-
- // Speaker notes
- { src: 'plugin/notes/notes.js', async: true },
-
- // MathJax
- { src: 'plugin/math/math.js', async: true }
- ]
-});
-```
-
-You can add your own extensions using the same syntax. The following properties are available for each dependency object:
-- **src**: Path to the script to load
-- **async**: [optional] Flags if the script should load after reveal.js has started, defaults to false
-- **callback**: [optional] Function to execute when the script has loaded
-- **condition**: [optional] Function which must return true for the script to be loaded
-
-### Ready Event
-
-A `ready` event is fired when reveal.js has loaded all non-async dependencies and is ready to start navigating. To check if reveal.js is already 'ready' you can call `Reveal.isReady()`.
-
-```javascript
-Reveal.addEventListener( 'ready', function( event ) {
- // event.currentSlide, event.indexh, event.indexv
-} );
-```
-
-Note that we also add a `.ready` class to the `.reveal` element so that you can hook into this with CSS.
-
-### Auto-sliding
-
-Presentations can be configured to progress through slides automatically, without any user input. To enable this you will need to tell the framework how many milliseconds it should wait between slides:
-
-```javascript
-// Slide every five seconds
-Reveal.configure({
- autoSlide: 5000
-});
-```
-
-When this is turned on a control element will appear that enables users to pause and resume auto-sliding. Alternatively, sliding can be paused or resumed by pressing »A« on the keyboard. Sliding is paused automatically as soon as the user starts navigating. You can disable these controls by specifying `autoSlideStoppable: false` in your reveal.js config.
-
-You can also override the slide duration for individual slides and fragments by using the `data-autoslide` attribute:
-
-```html
-
- After 2 seconds the first fragment will be shown.
- After 10 seconds the next fragment will be shown.
- Now, the fragment is displayed for 2 seconds before the next slide is shown.
-
-```
-
-To override the method used for navigation when auto-sliding, you can specify the `autoSlideMethod` setting. To only navigate along the top layer and ignore vertical slides, set this to `Reveal.navigateRight`.
-
-Whenever the auto-slide mode is resumed or paused the `autoslideresumed` and `autoslidepaused` events are fired.
-
-### Keyboard Bindings
-
-If you're unhappy with any of the default keyboard bindings you can override them using the `keyboard` config option:
-
-```javascript
-Reveal.configure({
- keyboard: {
- 13: 'next', // go to the next slide when the ENTER key is pressed
- 27: function() {}, // do something custom when ESC is pressed
- 32: null // don't do anything when SPACE is pressed (i.e. disable a reveal.js default binding)
- }
-});
-```
-
-### Vertical Slide Navigation
-
-Slides can be nested within other slides to create vertical stacks (see [Markup](#markup)). When presenting, you use the left/right arrows to step through the main (horizontal) slides. When you arrive at a vertical stack you can optionally press the up/down arrows to view the vertical slides or skip past them by pressing the right arrow. Here's an example showing a bird's-eye view of what this looks like in action:
-
-
-
-#### Navigation Mode
-You can fine tune the reveal.js navigation behavior by using the `navigationMode` config option. Note that these options are only useful for presentations that use a mix of horizontal and vertical slides. The following navigation modes are available:
-
-| Value | Description |
-| :--------------------------- | :---------- |
-| default | Left/right arrow keys step between horizontal slides. Up/down arrow keys step between vertical slides. Space key steps through all slides (both horizontal and vertical). |
-| linear | Removes the up/down arrows. Left/right arrows step through all slides (both horizontal and vertical). |
-| grid | When this is enabled, stepping left/right from a vertical stack to an adjacent vertical stack will land you at the same vertical index.
Consider a deck with six slides ordered in two vertical stacks:
`1.1` `2.1`
`1.2` `2.2`
`1.3` `2.3`
If you're on slide 1.3 and navigate right, you will normally move from 1.3 -> 2.1. With navigationMode set to "grid" the same navigation takes you from 1.3 -> 2.3. |
-
-### Touch Navigation
-
-You can swipe to navigate through a presentation on any touch-enabled device. Horizontal swipes change between horizontal slides, vertical swipes change between vertical slides. If you wish to disable this you can set the `touch` config option to false when initializing reveal.js.
-
-If there's some part of your content that needs to remain accessible to touch events you'll need to highlight this by adding a `data-prevent-swipe` attribute to the element. One common example where this is useful is elements that need to be scrolled.
-
-### Lazy Loading
-
-When working on presentation with a lot of media or iframe content it's important to load lazily. Lazy loading means that reveal.js will only load content for the few slides nearest to the current slide. The number of slides that are preloaded is determined by the `viewDistance` configuration option.
-
-To enable lazy loading all you need to do is change your `src` attributes to `data-src` as shown below. This is supported for image, video, audio and iframe elements.
-
-```html
-
- ![]()
-
-
-
-```
-
-#### Lazy Loading Iframes
-
-Note that lazy loaded iframes ignore the `viewDistance` configuration and will only load when their containing slide becomes visible. Iframes are also unloaded as soon as the slide is hidden.
-
-When we lazy load a video or audio element, reveal.js won't start playing that content until the slide becomes visible. However there is no way to control this for an iframe since that could contain any kind of content. That means if we loaded an iframe before the slide is visible on screen it could begin playing media and sound in the background.
-
-You can override this behavior with the `data-preload` attribute. The iframe below will be loaded
-according to the `viewDistance`.
-
-```html
-
-
-
-```
-
-You can also change the default globally with the `preloadIframes` configuration option. If set to
-`true` ALL iframes with a `data-src` attribute will be preloaded when within the `viewDistance`
-regardless of individual `data-preload` attributes. If set to `false`, all iframes will only be
-loaded when they become visible.
-
-### API
-
-The `Reveal` object exposes a JavaScript API for controlling navigation and reading state:
-
-```javascript
-// Navigation
-Reveal.slide( indexh, indexv, indexf );
-Reveal.left();
-Reveal.right();
-Reveal.up();
-Reveal.down();
-Reveal.prev();
-Reveal.next();
-Reveal.prevFragment();
-Reveal.nextFragment();
-
-// Randomize the order of slides
-Reveal.shuffle();
-
-// Toggle presentation states, optionally pass true/false to force on/off
-Reveal.toggleOverview();
-Reveal.togglePause();
-Reveal.toggleAutoSlide();
-
-// Shows a help overlay with keyboard shortcuts, optionally pass true/false
-// to force on/off
-Reveal.toggleHelp();
-
-// Change a config value at runtime
-Reveal.configure({ controls: true });
-
-// Returns the present configuration options
-Reveal.getConfig();
-
-// Fetch the current scale of the presentation
-Reveal.getScale();
-
-// Retrieves the previous and current slide elements
-Reveal.getPreviousSlide();
-Reveal.getCurrentSlide();
-
-Reveal.getIndices(); // { h: 0, v: 0, f: 0 }
-Reveal.getSlidePastCount();
-Reveal.getProgress(); // (0 == first slide, 1 == last slide)
-Reveal.getSlides(); // Array of all slides
-Reveal.getTotalSlides(); // Total number of slides
-
-// Returns an array with all horizontal/vertical slides in the deck
-Reveal.getHorizontalSlides();
-Reveal.getVerticalSlides();
-
-// Checks if the presentation contains two or more
-// horizontal/vertical slides
-Reveal.hasHorizontalSlides();
-Reveal.hasVerticalSlides();
-
-// Returns the speaker notes for the current slide
-Reveal.getSlideNotes();
-
-// State checks
-Reveal.isFirstSlide();
-Reveal.isLastSlide();
-Reveal.isOverview();
-Reveal.isPaused();
-Reveal.isAutoSliding();
-
-// Returns the top-level DOM element
-Reveal.getRevealElement(); // ...
-```
-
-### Custom Key Bindings
-
-Custom key bindings can be added and removed using the following Javascript API. Custom key bindings will override the default keyboard bindings, but will in turn be overridden by the user defined bindings in the ``keyboard`` config option.
-
-```javascript
-Reveal.addKeyBinding( binding, callback );
-Reveal.removeKeyBinding( keyCode );
-```
-
-For example
-
-```javascript
-// The binding parameter provides the following properties
-// keyCode: the keycode for binding to the callback
-// key: the key label to show in the help overlay
-// description: the description of the action to show in the help overlay
-Reveal.addKeyBinding( { keyCode: 84, key: 'T', description: 'Start timer' }, function() {
- // start timer
-} )
-
-// The binding parameter can also be a direct keycode without providing the help description
-Reveal.addKeyBinding( 82, function() {
- // reset timer
-} )
-```
-
-This allows plugins to add key bindings directly to Reveal so they can
-
-* make use of Reveal's pre-processing logic for key handling (for example, ignoring key presses when paused); and
-* be included in the help overlay (optional)
-
-### Slide Changed Event
-
-A `slidechanged` event is fired each time the slide is changed (regardless of state). The event object holds the index values of the current slide as well as a reference to the previous and current slide HTML nodes.
-
-Some libraries, like MathJax (see [#226](https://github.com/hakimel/reveal.js/issues/226#issuecomment-10261609)), get confused by the transforms and display states of slides. Often times, this can be fixed by calling their update or render function from this callback.
-
-```javascript
-Reveal.addEventListener( 'slidechanged', function( event ) {
- // event.previousSlide, event.currentSlide, event.indexh, event.indexv
-} );
-```
-
-### Presentation State
-
-The presentation's current state can be fetched by using the `getState` method. A state object contains all of the information required to put the presentation back as it was when `getState` was first called. Sort of like a snapshot. It's a simple object that can easily be stringified and persisted or sent over the wire.
-
-```javascript
-Reveal.slide( 1 );
-// we're on slide 1
-
-var state = Reveal.getState();
-
-Reveal.slide( 3 );
-// we're on slide 3
-
-Reveal.setState( state );
-// we're back on slide 1
-```
-
-### Slide States
-
-If you set `data-state="somestate"` on a slide ``, "somestate" will be applied as a class on the document element when that slide is opened. This allows you to apply broad style changes to the page based on the active slide.
-
-Furthermore you can also listen to these changes in state via JavaScript:
-
-```javascript
-Reveal.addEventListener( 'somestate', function() {
- // TODO: Sprinkle magic
-}, false );
-```
-
-### Slide Backgrounds
-
-Slides are contained within a limited portion of the screen by default to allow them to fit any display and scale uniformly. You can apply full page backgrounds outside of the slide area by adding a `data-background` attribute to your `` elements. Four different types of backgrounds are supported: color, image, video and iframe.
-
-#### Color Backgrounds
-
-All CSS color formats are supported, including hex values, keywords, `rgba()` or `hsl()`.
-
-```html
-
- Color
-
-```
-
-#### Image Backgrounds
-
-By default, background images are resized to cover the full page. Available options:
-
-| Attribute | Default | Description |
-| :------------------------------- | :--------- | :---------- |
-| data-background-image | | URL of the image to show. GIFs restart when the slide opens. |
-| data-background-size | cover | See [background-size](https://developer.mozilla.org/docs/Web/CSS/background-size) on MDN. |
-| data-background-position | center | See [background-position](https://developer.mozilla.org/docs/Web/CSS/background-position) on MDN. |
-| data-background-repeat | no-repeat | See [background-repeat](https://developer.mozilla.org/docs/Web/CSS/background-repeat) on MDN. |
-| data-background-opacity | 1 | Opacity of the background image on a 0-1 scale. 0 is transparent and 1 is fully opaque. |
-
-```html
-
- Image
-
-
- This background image will be sized to 100px and repeated
-
-```
-
-#### Video Backgrounds
-
-Automatically plays a full size video behind the slide.
-
-| Attribute | Default | Description |
-| :--------------------------- | :------ | :---------- |
-| data-background-video | | A single video source, or a comma separated list of video sources. |
-| data-background-video-loop | false | Flags if the video should play repeatedly. |
-| data-background-video-muted | false | Flags if the audio should be muted. |
-| data-background-size | cover | Use `cover` for full screen and some cropping or `contain` for letterboxing. |
-| data-background-opacity | 1 | Opacity of the background video on a 0-1 scale. 0 is transparent and 1 is fully opaque. |
-
-```html
-
- Video
-
-```
-
-#### Iframe Backgrounds
-
-Embeds a web page as a slide background that covers 100% of the reveal.js width and height. The iframe is in the background layer, behind your slides, and as such it's not possible to interact with it by default. To make your background interactive, you can add the `data-background-interactive` attribute.
-
-```html
-
- Iframe
-
-```
-
-Iframes are lazy-loaded when they become visible. If you'd like to preload iframes ahead of time, you can append a `data-preload` attribute to the slide ``. You can also enable preloading globally for all iframes using the `preloadIframes` configuration option.
-
-#### Background Transitions
-
-Backgrounds transition using a fade animation by default. This can be changed to a linear sliding transition by passing `backgroundTransition: 'slide'` to the `Reveal.initialize()` call. Alternatively you can set `data-background-transition` on any section with a background to override that specific transition.
-
-
-### Parallax Background
-
-If you want to use a parallax scrolling background, set the first two properties below when initializing reveal.js (the other two are optional).
-
-```javascript
-Reveal.initialize({
-
- // Parallax background image
- parallaxBackgroundImage: '', // e.g. "https://s3.amazonaws.com/hakim-static/reveal-js/reveal-parallax-1.jpg"
-
- // Parallax background size
- parallaxBackgroundSize: '', // CSS syntax, e.g. "2100px 900px" - currently only pixels are supported (don't use % or auto)
-
- // Number of pixels to move the parallax background per slide
- // - Calculated automatically unless specified
- // - Set to 0 to disable movement along an axis
- parallaxBackgroundHorizontal: 200,
- parallaxBackgroundVertical: 50
-
-});
-```
-
-Make sure that the background size is much bigger than screen size to allow for some scrolling. [View example](http://revealjs.com/?parallaxBackgroundImage=https%3A%2F%2Fs3.amazonaws.com%2Fhakim-static%2Freveal-js%2Freveal-parallax-1.jpg¶llaxBackgroundSize=2100px%20900px).
-
-### Slide Transitions
-
-The global presentation transition is set using the `transition` config value. You can override the global transition for a specific slide by using the `data-transition` attribute:
-
-```html
-
- This slide will override the presentation transition and zoom!
-
-
-
- Choose from three transition speeds: default, fast or slow!
-
-```
-
-You can also use different in and out transitions for the same slide:
-
-```html
-
- The train goes on …
-
-
- and on …
-
-
- and stops.
-
-
- (Passengers entering and leaving)
-
-
- And it starts again.
-
-```
-You can choose from `none`, `fade`, `slide`, `convex`, `concave` and `zoom`.
-### Internal links
-
-It's easy to link between slides. The first example below targets the index of another slide whereas the second targets a slide with an ID attribute (``):
-
-```html
-Link
-Link
-```
-
-You can also add relative navigation links, similar to the built in reveal.js controls, by appending one of the following classes on any element. Note that each element is automatically given an `enabled` class when it's a valid navigation route based on the current slide.
-
-```html
-
-
-
-
-
-
-```
-
-### Fragments
-
-Fragments are used to highlight individual elements on a slide. Every element with the class `fragment` will be stepped through before moving on to the next slide. Here's an example: http://revealjs.com/#/fragments
-
-The default fragment style is to start out invisible and fade in. This style can be changed by appending a different class to the fragment:
-
-```html
-
- grow
- shrink
- strike
- fade-out
- fade-up (also down, left and right!)
- fades in, then out when we move to the next step
- fades in, then obfuscate when we move to the next step
- blue only once
- highlight-red
- highlight-green
- highlight-blue
-
-```
-
-Multiple fragments can be applied to the same element sequentially by wrapping it, this will fade in the text on the first step and fade it back out on the second.
-
-```html
-
-
- I'll fade in, then out
-
-
-```
-
-The display order of fragments can be controlled using the `data-fragment-index` attribute.
-
-```html
-
- Appears last
- Appears first
- Appears second
-
-```
-
-### Fragment events
-
-When a slide fragment is either shown or hidden reveal.js will dispatch an event.
-
-Some libraries, like MathJax (see #505), get confused by the initially hidden fragment elements. Often times this can be fixed by calling their update or render function from this callback.
-
-```javascript
-Reveal.addEventListener( 'fragmentshown', function( event ) {
- // event.fragment = the fragment DOM element
-} );
-Reveal.addEventListener( 'fragmenthidden', function( event ) {
- // event.fragment = the fragment DOM element
-} );
-```
-
-### Code Syntax Highlighting
-
-By default, Reveal is configured with [highlight.js](https://highlightjs.org/) for code syntax highlighting. To enable syntax highlighting, you'll have to load the highlight plugin ([plugin/highlight/highlight.js](plugin/highlight/highlight.js)) and a highlight.js CSS theme (Reveal comes packaged with the Monokai themes: [lib/css/monokai.css](lib/css/monokai.css)).
-
-```javascript
-Reveal.initialize({
- // More info https://github.com/hakimel/reveal.js#dependencies
- dependencies: [
- { src: 'plugin/highlight/highlight.js', async: true },
- ]
-});
-```
-
-Below is an example with clojure code that will be syntax highlighted. When the `data-trim` attribute is present, surrounding whitespace is automatically removed. HTML will be escaped by default. To avoid this, for example if you are using `` to call out a line of code, add the `data-noescape` attribute to the `` element.
-
-```html
-
-
-(def lazy-fib
- (concat
- [0 1]
- ((fn rfib [a b]
- (lazy-cons (+ a b) (rfib b (+ a b)))) 0 1)))
-
-
-```
-
-#### Line Numbers & Highlights
-
-To enable line numbers, add `data-line-numbers` to your `` tags. If you want to highlight specific lines you can provide a comma separated list of line numbers using the same attribute. For example, in the following example lines 4 and 8-11 are highlighted:
-
-```html
-
-import React, { useState } from 'react';
-
-function Example() {
- const [count, setCount] = useState(0);
-
- return (
-
- You clicked {count} times
-
-
- );
-}
-
-```
-
-
-
-#### Step-by-step Highlights
-
-You can step through multiple code highlights on the same code block. Delimit each of your highlight steps with the `|` character. For example `data-line-numbers="1|2-3|4,6-10"` will produce three steps. It will start by highlighting line 1, next step is lines 2-3, and finally line 4 and 6 through 10.
-
-
-
-### Slide number
-
-If you would like to display the page number of the current slide you can do so using the `slideNumber` and `showSlideNumber` configuration values.
-
-```javascript
-// Shows the slide number using default formatting
-Reveal.configure({ slideNumber: true });
-
-// Slide number formatting can be configured using these variables:
-// "h.v": horizontal . vertical slide number (default)
-// "h/v": horizontal / vertical slide number
-// "c": flattened slide number
-// "c/t": flattened slide number / total slides
-Reveal.configure({ slideNumber: 'c/t' });
-
-// You can provide a function to fully customize the number:
-Reveal.configure({ slideNumber: function( slide ) {
- // Ignore numbering of vertical slides
- return [ Reveal.getIndices( slide ).h ];
-}});
-
-// Control which views the slide number displays on using the "showSlideNumber" value:
-// "all": show on all views (default)
-// "speaker": only show slide numbers on speaker notes view
-// "print": only show slide numbers when printing to PDF
-Reveal.configure({ showSlideNumber: 'speaker' });
-```
-
-### Overview mode
-
-Press »ESC« or »O« keys to toggle the overview mode on and off. While you're in this mode, you can still navigate between slides,
-as if you were at 1,000 feet above your presentation. The overview mode comes with a few API hooks:
-
-```javascript
-Reveal.addEventListener( 'overviewshown', function( event ) { /* ... */ } );
-Reveal.addEventListener( 'overviewhidden', function( event ) { /* ... */ } );
-
-// Toggle the overview mode programmatically
-Reveal.toggleOverview();
-```
-
-### Fullscreen mode
-
-Just press »F« on your keyboard to show your presentation in fullscreen mode. Press the »ESC« key to exit fullscreen mode.
-
-### Embedded media
-
-Add `data-autoplay` to your media element if you want it to automatically start playing when the slide is shown:
-
-```html
-
-```
-
-If you want to enable or disable autoplay globally, for all embedded media, you can use the `autoPlayMedia` configuration option. If you set this to `true` ALL media will autoplay regardless of individual `data-autoplay` attributes. If you initialize with `autoPlayMedia: false` NO media will autoplay.
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-Note that embedded HTML5 ` 
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