using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Enter a number");

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

        double FactorialVal = Factorial(number);

        Console.WriteLine("Factorial of " + number + " = " + FactorialVal);

    }

    public static double Factorial( int number)

    {

        if (number == 0)

            return 1;

        else

            return number * Factorial(number - 1);

    }

}