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 Java (OpenJDK 11.0.6) (judge verdict: Accepted)

import java.util.Scanner;
import java.util.stream.IntStream;

public class Main {

	/** 入力文字列の数 */
	private static final int N = 3;

	public static void main(String[] args) {
		try (Scanner scanner = new Scanner(System.in)) {
			char[][] s = new char[N][];
			IntStream.range(0, N).forEach(i -> s[i] = scanner.next().toCharArray());
			boolean result = true;
			for (int i = 1; i < N; i++) {
				// 直前の文字列の最後の文字と現在の文字列の最初の文字と比較
				if (s[i - 1][s[i - 1].length - 1] != s[i][0]) {
					result = false;
					break;
				}
			}
			System.out.println(result ? "YES" : "NO");
		}
	}
}