title: find a 6 digit number in String
body: <p>I've a String from a SMS like:</p>
  
  <p>"Your code: 123456. Your reference number is 012. The total amount is E 1250,00.."</p>
  
  <p>Now I need to extract the code '123456', which is different every time, but always 6 digits.</p>
  
  <p>How can I extract this 6 digit number from the string? Can I use Regex expressions somehow? I need to be sure, so I don't want to split on 'code: ' for example.</p>
  
  <p>EDIT:
  The rest of the text can be different, but there will be only 6 digits in the SMS.</p>