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 Lua (5.3.2) (judge verdict: Accepted)

local tmp = io.read("l") .. ' @'
local prev = ' '
local c = ' '
local cnt = 0
for i=1,#tmp do
    c = string.sub(tmp, i, i)
    if c == ' ' then
        if prev == string.sub(tmp, i+1,i+1) then
            cnt = cnt + 1
            if cnt == 2 then
                print('YES')
                return
            end
        else
            print('NO')
            return
        end
    end
    prev = c
end