Problem:
Score : 100 points

Problem Statement

We have a 3×3 square grid, where each square contains a lowercase English letters.
The letter in the square at the i-th row from the top and j-th column from the left is c_{ij}.

Print the string of length 3 that can be obtained by concatenating the letters in the squares on the diagonal connecting the top-left and bottom-right corner of the grid, from the top-left to bottom-right.

Constraints

Input consists of lowercase English letters.

Input

Input is given from Standard Input in the following format:

c_{11}c_{12}c_{13}
c_{21}c_{22}c_{23}
c_{31}c_{32}c_{33}

Output

Print the string of length 3 that can be obtained by concatenating the letters on the diagonal connecting the top-left and bottom-right corner of the grid, from the top-left to bottom-right.

Sample Input 1

ant
obe
rec

Sample Output 1

abc

The letters in the squares on the diagonal connecting the top-left and bottom-right corner of the grid are a, b and c from top-right to bottom-left. Concatenate these letters and print abc.

Sample Input 2

edu
cat
ion

Sample Output 2

ean

Solution in C# (Mono 4.6.2.0) (judge verdict: Runtime Error)

using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
using static System.Console;
class Program
{
    static void Main()
    {
        //入力
        //int[] input = Console.ReadLine().Split().Select(i => int.Parse(i)).ToArray();
        //string input= Console.ReadLine();
        string[] input = new string[4];
        for (int a = 0; a < 4; a++)
        {
            input[a] = Console.ReadLine();
        }
        //int input =int.Parse(input[0]+""+input[3+1]+""+input[3*2+2]);
        Console.WriteLine(int.Parse(input[0][0] + "" + input[1][1] + "" + input[2][2]));


        /*
        //処理速度計測
        var sw = new System.Diagnostics.Stopwatch();
        sw.Start();
        //解法
 
        //処理速度表示
        sw.Stop();
        TimeSpan ts = sw.Elapsed;
        Console.WriteLine((int)(Math.Floor((ts).TotalMilliseconds))+"ms");
        */
        Console.ReadLine();

    }
}