Big Factorial

using System;
using System.Numerics;


    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            BigInteger result = 1;

            for (int i=1; i <= n ;  i++)
            {
               result *= i;
            }
            Console.WriteLine(result);
        }
    }