Problem:
Score : 100 points

Problem Statement

You are given three strings A, B and C. Check whether they form a word chain.

More formally, determine whether both of the following are true:

The last character in A and the initial character in B are the same.

The last character in B and the initial character in C are the same.

If both are true, print YES. Otherwise, print NO.

Constraints

A, B and C are all composed of lowercase English letters (a - z).

1 ≤ |A|, |B|, |C| ≤ 10, where |A|, |B| and |C| are the lengths of A, B and C, respectively.

Input

Input is given from Standard Input in the following format:

A B C

Output

Print YES or NO.

Sample Input 1

rng gorilla apple

Sample Output 1

YES

They form a word chain.

Sample Input 2

yakiniku unagi sushi

Sample Output 2

NO

A and B form a word chain, but B and C do not.

Sample Input 3

a a a

Sample Output 3

YES

Sample Input 4

aaaaaaaaab aaaaaaaaaa aaaaaaaaab

Sample Output 4

NO

Solution in PHP (5.6.30) (judge verdict: Wrong Answer)

<?php
$stdins = [];
for($i = 0; $i < 4; $i++) {
	$stdins[$i] = trim(fgets(STDIN));
}

$flg_check = false;

$a = substr($stdins[0], -1);
$b = substr($stdins[1], -1);
$c = substr($stdins[2], -1);

if($a == $b && $b == $c) $flg_check = true;

if($flg_check) printf('YES\n');
printf('NO\n');
?>