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<script type="text/javascript" src="https://vk.com/js/api/openapi.js?162"></script>
<script type="text/javascript">
VK.init({apiId: 7221503, onlyWidgets: true});
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<div id="vk_comments"></div>
<script type="text/javascript">
VK.Widgets.Comments("vk_comments", {limit: 20, attach: "*"});
</script>