using System;

public class Program

{

    public static void Main()

    {

        int i,x;

        double r;

        r=1;

        Console.WriteLine("insert the number");

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

        for (i=1;i<=x;i++)

            r=r*i;

        if (x==0)

            Console.WriteLine("0! = 1");

        if (x>0)

            Console.WriteLine("{0}! = {1}",x,r);

    }

}