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)

#[allow(unused_imports)]
use std::io;
#[allow(unused_imports)]
use std::cmp;

#[allow(dead_code)]
fn getline() -> Vec<String> {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok().unwrap();
    s.split(' ').map(|x| x.trim().to_string()).collect::<Vec<String>>()
}

#[allow(dead_code)]
fn get<T: std::str::FromStr>(s: &String) -> T {
    s.parse().ok().unwrap()
}

fn main() {
    let abc = getline().into_iter()
        .map(|s| s.chars().collect::<Vec<_>>()).collect::<Vec<_>>();
    for i in 0..2 {
        if abc[i].last() != abc[i+1].first() {
            println!("NO");
            return;
        }
    }
    println!("YES");
}