using System;

public class Program

{

    public static void Main()

    {

        countdown(10);      

    }

    public static void countdown(int x)

    {

    if (x == 0)

    {

    Console.WriteLine("Done!");

    }

        else{

        Console.WriteLine("{0} ...",x);

            countdown(x-1); 

        }

    }

}

​

​