using System;

using System.Text;

public class Program

{

    public static StringBuilder sb = new StringBuilder();

    public static void Main()

    {

        string reverseThis = "Hello World";

        char[] array = reverseThis.ToCharArray();

        GetLastChar(array, array.Length-1);

        Console.WriteLine(sb.ToString());

    }

    public static void GetLastChar(char[] reverseThis, int position){

        sb.Append(reverseThis[position]);

        if(position > 0)

        {

            GetLastChar(reverseThis,position-1);

        }

    }

}