title: Regex for three letters and four numbers?
body: <p>I have this regex I am supposed to create that accepts the following formats:</p>
  
  <ol>
  <li>Any 3 letters (case-insensitive, no other characters except for alphabetic characters) </li>
  <li>Any 2 letters with a dash in between (case-insensitive)</li>
  <li>Any 4 digits</li>
  </ol>
  
  <p>This is what I have come up with so far: <code>^([a-zA-Z]([a-zA-Z]|-)[a-zA-Z])|[0-9]{4}$</code></p>
  
  <p>The issue with this regex is that it accepts a combination of 4 letters as well, but I only want three consecutive letters. What do I need to change in my regex to accomplish this?</p>