HTML is to describe a web document a markup language. Used for the development of web pages, it is in Angle brackets to mark a page tags, like
<HTML>
<body>
<h1>My First Heading</h1>
<p>My first paragraph.</p>
</body>
</HTML>
<HTML> is the beginning of the HTML tags.</HTML> is the end of HTML tags.
<h1>My First Heading</h1> is the content of the "My First Heading".
Each tag contains the beginning tag and end tag.
There is a string, it has a lot of tags (there are no content in these tags), Now you should judge the string whether conform to the standard.
For each case,if the string conform to the standard, print "Yes", otherwise print "No".
