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 Rust (1.15.1) (judge verdict: Accepted)

fn main() {
    use std::io;

    let mut input = String::new();
    let _ = io::stdin().read_line(&mut input);
    let strings = input.trim().split_whitespace().collect::<Vec<_>>();

    let (afirst, atail) = strings[0].split_at(1);
    let (bfirst, btail) = strings[1].split_at(1);
    let (cfirst, _) = strings[2].split_at(1);

    let alast = atail.to_string().pop().unwrap_or(afirst.clone().to_string().pop().unwrap());
    let blast = btail.to_string().pop().unwrap_or(bfirst.clone().to_string().pop().unwrap());

    if alast.to_string() == bfirst.to_string() && blast.to_string() == cfirst.to_string() {
        println!("YES");
    } else {
        println!("NO");
    }

}