using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Enter Number");

        int number=Convert.ToInt32(Console.ReadLine());

        double factorial=Factorial(number);

        Console.WriteLine("Factorial is" +number+ "=" +factorial.ToString());

    }

    public static double Factorial(int number)

    {

        if(number==0)

            return 1;

        return number*Factorial(number-1);

    }

}