using System;

public class Program

{

    public static void Main()

    {

        string str= "";

        str = Console.ReadLine();

        Console.WriteLine(Environment.NewLine);

        Console.WriteLine("Output:");

        Console.WriteLine(Environment.NewLine);

        string res= str;

        Console.WriteLine(res);

        Console.WriteLine(Environment.NewLine);

        do{

            res = func(res);

            Console.WriteLine(res);

            Console.WriteLine(Environment.NewLine);

        }while(!str.Equals(res));

        str = Console.ReadLine();

        //Console.WriteLine(func("This is a book and a dog"));

    }

    public static string func(string str){

        string res = "";

        string[] strArray= str.Split(' ');

        int len = strArray.Length -1;

        if(strArray.Length % 2 == 0){

            for(int i = 0;i < strArray.Length/2 ;i++){

                res = res + strArray[len - i] + " " + strArray[i] + " ";

            }

        }else{

          for(int i = 0;i < strArray.Length/2 ;i++){

                res = res + strArray[len - i] + " " + strArray[i] + " ";

            }

            res = res + strArray[len/2];

        }

        return res.Replace("  "," ").Trim();

    }   

}