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
# 整数の入力
//fscanf(STDIN, "%d", $a);
# スペース区切りの整数の入力
fscanf(STDIN, "%s %s %s", $a, $b, $c);
# 文字列の入力
//fscanf(STDIN, "%s", $s);

if ($a{(strlen($a)-1)} != $b{0}){
    exit('NO');
}

if ($b{(strlen($b)-1)} != $c{0}){
    exit('NO');
}
exit('YES');
//echo $a{0} . $b{} . $c;

# 出力
// echo ($a+$b+$c)." ".$s."\n";