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 PHP7 (7.0.15) (judge verdict: Accepted)

<?php
/*
    Problem URL : http://abc060.contest.atcoder.jp/tasks/abc060_a

    Score  :
    Result :
    Time   : ms
    Memory : KB
 */

list($A, $B, $C) = explode(" ", trim(fgets(STDIN)));

$Alast = substr($A, -1, 1);
$Bfirst = substr($B, 0, 1);
$Blast = substr($B, -1, 1);
$Cfirst = substr($C, 0, 1);

if (($Alast == $Bfirst) && ($Blast == $Cfirst)) {
    echo "YES\n";
} else {
    echo "NO\n";
}