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: Accepted)

using System;
using System.Linq;
using System.Collections.Generic;
using static System.Console;
using static System.Math;
 
public class Hello{
    public static void Main(){
/*        string[] input = ReadLine().Split(' ');
        int n = int.Parse(input[0]);
        int m = int.Parse(input[1]);
        int a = int.Parse(input[2]);
        int b = int.Parse(input[3]);*/
//        string temp = ReadLine();
//        int a = int.Parse(ReadLine());
//        int b = int.Parse(ReadLine());
//        int c = int.Parse(ReadLine());
        string a = ReadLine();
        string b = ReadLine();
        string c = ReadLine();
        Write(a[0]);
        Write(b[1]);
        Write(c[2]);
        WriteLine();
    }
}