using System;

public class Program

{

    public static void Main()

    {

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

        Console.WriteLine(Factoriel(n));        

    }

public static long Factoriel(int n);

    {

        if (n == 0 , n == 1)

        {

            return 1; 

        }

        else

        { 

            Console.WriteLine($"n {Factoriel(n - 1)}");

            return n * Factoriel(n - 1);

        }