using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        Console.WriteLine(reverse(1000));

    }

    public static int reverse(int inp) {

        string newNum = "";

        string inpStr = Math.Abs(inp).ToString();

        for(int i = inpStr.Length - 1; i >= 0; i--){

            newNum += inpStr[i];

        }

        return Int32.Parse(newNum) * (inp < 0? -1: 1);

    }

}