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 Java8 (OpenJDK 1.8.0) (judge verdict: Runtime Error)

import java.util.*;

class Main {
   public static void main(String[] args)
   {
      Scanner scan = new Scanner(System.in);
      int     N = scan.nextInt();
      int     K = scan.nextInt();
      long    n = 1, coun = 0;

      for(int i = 1; i <= N; i++){
          for(long j = n; j <= N; j++){
              if(i - j * (i / j) >= K){
                 //System.out.print(i);
                 //System.out.println(j);
                 coun++;
                 }
              if(coun == 1 && n == 1){
                 if(i != 1){
                    n = i - 1;
                    }
                 }
              }
          }
      System.out.println(coun);
   }
}