using System;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

​

            string expression =@"\d{3}-\d{8}-\d{3}\)";

​

        Regex regex = new Regex(expression);

    //Regex reg = new Regex (@"\(\d{3}\)-\d{8}-\(\d{3}\)");

    bool result2 =  regex.IsMatch("123-12345678-123)"); 

    //Regex matches = Regex.Match("(123)-12345678-(123)", rega);

​

    // this means it did in fact match the input

    //if (matches.Success)

        Console.WriteLine(result2);

    }

}