using System;
//using System.Collections.Generic;
//using System.Text;
namespace digui1
{
public class Program
{
public static void Main()
{
int n;
n = int.Parse(Console.ReadLine());
Console.WriteLine("{0}!={1}.", n, fun(n));
Console.ReadLine();
}
public static int fun(int n)
{
if (n <= 1)
return 1;
else
return n * fun(n - 1);
}
}
}