using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Enter a number please");

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

        ulong fact = 1;

        for(ulong i = 1; i <=n; i++)

            {fact = 1;}

        Console.WriteLine("n! = " + fact);

    }

}