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: Accepted)

<?php

$string = trim(fgets(STDIN));

$parts = explode(" ", $string);


for ($i = 0; $i < count($parts) - 1; $i ++)
{


	//last char of first work
	$last = substr($parts[$i], -1, 1);



	$first	 = substr($parts[$i + 1], 0, 1);

	if ($first != $last)
	{
		echo "NO\n";
		die();
	}
}

echo "YES\n";
die();