using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace contest
{
    class Program
    {
        static void Main(string[] args)
        {
            int N = int.Parse(Console.ReadLine());
            Console.WriteLine(Count(N));
        }

        static public int Count(int N)
        {
            int min = (int)Math.Pow(2, N) - 1;
            int max = (int)Math.Pow(2, N * 2);

            int patCnt = 0;
            for (int i = min; i < max; i++)
            {
                int t = i;
                int cnt0 = 0;
                int cnt1 = 0;
                int n = 0;
                bool isOk = true;
                for (; n < N * 2 ; n++)
                {

                    if ((t & 1) == 1) cnt1++;
                    else cnt0++;
                    if (cnt0 > cnt1 || cnt1 > N) { isOk = false; break; }

                    t >>= 1;

                }
                if (isOk)
                {
                    patCnt++;
                }
            }
            return patCnt;
        }
    }
}