title: Regular expression to accept only greek characters
body: <p>I have this regular expression <code>^[A-Za-z]{2,3}[0-9]{3,4}$</code> with which I validate in an input field so that it has 2 or 3 letters and 3 or 4 numbers</p>
  
  <p>I want to accept only greek characters.</p>
  
  <p>I tried this <code>^[α-ωΑ-Ω]{2,3}[0-9]{3,4}$</code> from <a href="https://stackoverflow.com/questions/6255329/php-and-regexp-to-accept-only-greek-characters-in-form">PHP and regexp to accept only Greek characters in form</a> but with no luck</p>
  
  <p>i also tried <code>^[\p{Greek}]{2,3}[0-9]{3,4}$</code> but again no luck</p>
  
  <p>Any suggestions?</p>
  
  <p>VALID STRINGS: ΚΚΞ542  OOP8888 ΠΠ8965
  INVALID STRINGS: 555555 K879 ΓΗΥΟ565</p>