Class Task 22#

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

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            int n, sum = 1;
            n = int.Parse(Console.ReadLine());
            for (; n > 0; n--)
            {
                sum = sum * n;
            }
            Console.WriteLine(sum);
            Console.ReadLine();
        }
    }
}