using System;

​

class Program

{

    static int Factorial(int n)

    {

        int child = 1;

        if (n > 1)

        {

            child = Factorial(n - 1);

        }

        int level = n * child;

        return level;

    }

​

    static void Main()

    {

        Console.WriteLine(Factorial(5));

    }

}