using System;

public class Program

{

    static int factorial (int n, int fact)

        {

            if (n>1)

            {

                fact = fact * n;

                n = n - 1;

                return factorial (n,fact);

            }

            else return fact;

        }

    public static void Main()

    {

        int answer = factorial (Convert.ToInt32(Console.ReadLine()), 1);

        Console.WriteLine(answer);

    }

}