Regular expression validator

String pattern = @"^(\w\d\w)( )(\d\w\d)$";
       String input = "A0A 0A0";
       Regex objRegEx = new Regex(pattern);
       MatchCollection result = objRegEx.Matches(input);
       if (result.Count>0)
       {
           for (int i = 0; i < result.Count; i++)
           {
               Response.Write(result[i].Value+"<br/>");
           }
       }