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 Python (3.4.3) (judge verdict: Accepted)

#!/usr/bin/env python3
import sys
sys.setrecursionlimit(300000)

YES = "YES"  # type: str
NO = "NO"  # type: str

def solve(A: str, B: str, C: str):
    ret = NO
    if A[-1] == B[0] and B[-1] == C[0]:
        ret = YES
    print(ret)
    return


def main():
    def iterate_tokens():
        for line in sys.stdin:
            for word in line.split():
                yield word
    tokens = iterate_tokens()
    A = next(tokens)  # type: str
    B = next(tokens)  # type: str
    C = next(tokens)  # type: str
    solve(A, B, C)

if __name__ == '__main__':
    main()