using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        double a = 1.80012;

        String mask = "0.0000";

        String input = "2";

        String ori = a.ToString();

        a = a+2;

        String output = "";

        Console.WriteLine("{0}",mask.Substring(mask.Length));

        /*

        for(int i = mask.Length ; i >= 0 ; i--){

            Console.WriteLine("{0}",ori[i]);

            input.Length

        }

        */

    }

}