using System;

public class Program

{

    public static void Main()

    {

        //judith squza garza

        int nu, fac = 1;

        Console.WriteLine("hey, write a number and I'll tell if its factorial.");

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

        for (int n = 1; n <= nu; n++)

        {

            fac =  fac * n ;

        }

        Console.WriteLine(nu + "! = " + fac);

    }

}