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 Java8 (OpenJDK 1.8.0) (judge verdict: Runtime Error)

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        int W = sc.nextInt();
        int[] w = new int[N];
        int[] v = new int[N];

        for (int i = 0; i < N; i++) {
            w[i] = sc.nextInt();
            v[i] = sc.nextInt();
        }

        long[][] dp = new long[w.length + 1][W + 1];
        long ret = 0L;
        for (int i = 0; i < w.length; i++) {
            for (int j = 0; j <= W; j++) {
                if (w[i] <= j) {
                    dp[i + 1][j] = Math.max(dp[i][j], dp[i][j - w[i]] + v[i]);
                    ret = Math.max(ret, dp[i + 1][j]);
                } else {
                    dp[i + 1][j] = dp[i][j];
                }
            }
        }
        System.out.println(ret);
    }
}