title: Regular expression to check 3 uppercase letters anywhere
body: <p>I want to write a regular expression that checks whether a string has 3 uppercase lettrs. Those letters need not to be one after the other.</p>
  
  <p>I know how to check whether a string has any uppercase letter by using (?=.*?[A-Z]) but i could not go beyond this</p>
  
  <pre><code>WsswFeA - will match
  AAtrW   - will match
  srABFes - will match
  srtZfgQ - will not match
  </code></pre>
  
  <p>pleas help me</p>