title: Regular Expression to match specific string
body: <p>RegEx has always been my Achilles' heel. I am writing web app, where user will input his identifier. I'm using <code>RegexValidator</code> to validate this input. </p>
  
  <p>The identifier should be something like this:</p>
  
  <pre class="lang-none prettyprint-override"><code>TN-In-PL-KW-2012-1234
  </code></pre>
  
  <p>And this is how the identifier is built:</p>
  
  <ul>
  <li>first two letters are always <code>TN</code></li>
  <li>followed by hyphen</li>
  <li>then two letters, that are either: <code>In</code>, <code>Te</code>, <code>Yo</code> or <code>Et</code></li>
  <li>hyphen</li>
  <li>two uppercase letters</li>
  <li>another hyphen</li>
  <li>another two uppercase letters</li>
  <li>hyphen</li>
  <li>four digits, that are a year, so something between 1970 and 2012 (I can ignore that as long as there are 4 digits)</li>
  <li>hyphen</li>
  <li>ordinal number that can have from 1 to 4 digits</li>
  </ul>
  
  <p>Please help me writing RegEx to match this identifier.</p>