I have the following to check if the phone number is in the following format 
 (XXX) XXX-XXXX. The below code always return true. Not sure why. 

```
   Match match = Regex.Match(input, @"((\(\d{3}\) ?)|(\d{3}-))?\d{3}-\d{4}");

    // Below code always return true
    if (match.Success) { ....}

```