title: RegExp for matching three letters, but not text "BUY"
body: <p>I have two buttons on form, one of the buttons contain currency code (EUR, USD, GBP,CHF,..) and another one - trade direction (BUY or SELL). And some utility recognize buttons by it's text. 
  To recognize button with currencies, I use Regular expression ":[A-Z]{3}", but it don't work properly when second button contain text "BUY" (regex description returns more than one object).</p>
  
  <p>Question: how can I write pattern for Regular expression, which means: match only when text contain three upper letters, but not text "BUY"?</p>
  
  <p>Thanks!</p>