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

namespace test
{
    class Program
    {
        static char open = '(';
        static char close = ')';
        static int N = 10;

        static void Main(string[] args)
        {
            List<string> list = new List<string>();
            GetStringList(ref list);
            Console.WriteLine(string.Join(',', list.ToArray()));
            Console.ReadKey();
        }

        private static void GetStringList(ref List<string> list)
        {
            foreach (var str in GetStrings(open.ToString()))
            {
                list.Add(str);
            }
        }

        private static IEnumerable<string> GetStrings(string tmp)
        {
            int prevOpen = Regex.Matches(tmp, "\\(").Count;
            int prevClose = Regex.Matches(tmp, "\\)").Count;

            if (tmp.Length == 2 * N) yield return tmp;

            else if (tmp.Length == 2 * N - 1) yield return (tmp + close);

            else if (prevOpen == prevClose)
            {
                tmp += open;
                foreach (var tmp2 in GetStrings(tmp))
                {
                    yield return tmp2;
                }
            }

            else if (prevOpen == N)
            {
                tmp += close;
                foreach (var tmp2 in GetStrings(tmp))
                {
                    yield return tmp2;
                }
            }

            else if (prevOpen < N)
            {
                var strings1 = GetStrings(tmp + open).ToList(); ;
                var strings2 = GetStrings(tmp + close).ToList();

                strings1.AddRange(strings2);
                foreach (var tmp3 in strings1) { yield return tmp3; }
            }

            yield break;
        }
    }
}