Using .NET Regular Expressions to match and capture nested parenthesis

gistfile1.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;

namespace TestRegex
{
    class Program
    {
        static void Main(string[] args)
        {
            var pattern2 = @"^(?>
 \( (?<LEVEL>)(?<CURRENT>)
|
 (?=\)) (?<LAST-CURRENT>) (?(?<=\(\k<LAST>) (?<-LEVEL> \)))
|
 [^()]?
)*
(?(DEPTH)(?!))$";

            var input = "2a+(3a-4)+(2b(3a-2))";

            var match = Regex.Match(input, pattern2, RegexOptions.IgnorePatternWhitespace);
            if (match.Success)
            {
                Console.WriteLine("Success");
                foreach (var capture in match.Groups["LAST"].Captures)
                {
                    Console.WriteLine(capture);
                }
            }

            Console.ReadKey(false);
        }
    }
}