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 Python (3.4.3) (judge verdict: Wrong Answer)

A=list(map(str, input().split()))
a=['']*3
b=['']*10
tmp1=''
tmp2=''
p=0
for i in range(3):
    a[i]=list(A[i])
    if i!=0:
        a[0]=tmp2
    if tmp1!='':
        if tmp1!=tmp2:
            p=1
    a[i]=reversed(a[i])
    b[i]=list(a[i])
    b[0]=tmp1
if p==0:
    print('YES')
else:
    print('NO')