using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("enter the string");

        string s=Console.ReadLine();

        string e="";

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

            int n=(int)((s.Length/2)-1);

        e=e+s.Substring(n,2)    ;

        }

        else

        {

            Console.WriteLine(" ente the even length string");

            return;

        }

        Console.WriteLine(e);

    }

}