using System;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        var teste = Regex.Match("(12) 3456-7890", @"\((\d{2})\)\s*(\d{4,5}\-\d{4})");

        Console.WriteLine(teste.Groups[0]);

        Console.WriteLine(teste.Groups[1]);

        Console.WriteLine(teste.Groups[2]);

    }

}