using System;

using System.Text;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        Program.ReverseWords("Hello World");

    }

    public static void ReverseWords(string str)

    {

        StringBuilder output = new StringBuilder();

        List<char> charlist = new List<char>();

        for(int i = 0; i< str.Length; i++)

        {

            if (str[i] == ' ' || i == str.Length - 1)

            {

                if(i == str.Length - 1)

                {

                    charlist.Add(str[i]);

                }

                for(int j = charlist.Count - 1; j >=0; j--)

                {

                    output.Append(charlist[j]);

                }

                output.Append(' ');

                charlist = new List<char>();

            }

            else {

                charlist.Add(str[i]);

            }

            Console.WriteLine(output.ToString());

        }

    }

}