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 C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;

namespace VirtualAtCorder
{
    class Program
    {



        static void Main(string[] args)
        {
            string[] inputs = Console.ReadLine().Split(' ');

            bool calc = false;

            string output = "";

            calc = Calc(inputs);

            for (int i = 0; i < inputs.Length; i++)
            {
                if(inputs[0].Length > 10)
                {
                    calc = false;
                    break;
                }
            }

            output = (calc) ? "YES" : "NO";

            Console.WriteLine(output);

            Console.ReadKey();
        }

        static bool Calc(string[] inputs)
        {
            bool result = false;

            if (inputs[0].Last() == inputs[1].First())
            {
                result = true;
            }
            else
            {
                return false;
            }
            if (inputs[1].Last() == inputs[2].First())
            {
                result = true;
            }
            else
            {
                result = false;
            }

            return result;
        }


    }
}