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 Go (1.6) (judge verdict: Accepted)

package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	
	ans := make([]byte, 3);
	for i := 0; i < 3; i++ {
	    text := ScanText(scanner)
	    ans[i] = text[i]
	}
	fmt.Println(string(ans))
}

func ScanInt(scanner *bufio.Scanner) int {
	scanner.Scan()
	i, e := strconv.Atoi(scanner.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func ScanFloat64(scanner *bufio.Scanner) float64 {
	scanner.Scan()
	f, e := strconv.ParseFloat(scanner.Text(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func ScanText(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}

func Max(a, b int) int {
	if a < b {
		return b
	}
	return a
}

func Min(a, b int) int {
	if a > b {
		return b
	}
	return a
}

func Abs(a int) int {
	if a < 0 {
		a *= -1
	}
	return a
}