using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;

namespace yukicore
{
     class Program
    {
        private static void Main()
        {
            //no597
            List<char> rtn=new List<char>();
            Console.ReadLine();
            while (true)
            {
                var str = Console.ReadLine();
                if (string.IsNullOrEmpty(str))
                    break;
                rtn.AddRange(str.ToCharArray());
            }
            Console.WriteLine(new string(rtn.ToArray()));
        }
    }
}