using System;

public class Program

{

    public static void Main()

    {

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

​

decimal factorial = 1;

​

while (true)

{

          if (n <= 1)

          {

                   break;

          }

          factorial *= n;

          n--;

}

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

    }

}