using System;

public class Program

{

    public static void Main()

    {

        // Samir Sáenz

        int num, tot = 1;

        Console.WriteLine("Hello ! Write a number and I´ll tell you it´s factorial");

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

        for (int i = 1; i <= num; i++)

        {

        tot *= i;

        }

            Console.WriteLine(num+"! = "+tot);

    }

}