using System;

using System.Numerics;

public class CatalanNumbersWithBigInteger

{

    public static void Main()

    {

           {

               Console.WriteLine("Please input number n:");

            int n = int.Parse(Console.ReadLine());

            if (1 < n && n < 100)

            {

                BigInteger numerator = 1;

                BigInteger denominator = 1;

                BigInteger result = 1;

                for (int k = 2; k <= n; k++)

                {

                    numerator *= n + k;

                    denominator *= k;

                }

                result = numerator / denominator;

                Console.WriteLine("Catalan number is {0}.",result);

            }

            else

            {

                Console.WriteLine("out of range");

            }      

        }

    }

}