Problem:
Score : 200 points

Problem Statement

A string S of an odd length is said to be a strong palindrome if and only if all of the following conditions are satisfied:

S is a palindrome.

Let N be the length of S. The string formed by the 1-st through ((N-1)/2)-th characters of S is a palindrome.

The string consisting of the (N+3)/2-st through N-th characters of S is a palindrome.

Determine whether S is a strong palindrome.

Constraints

S consists of lowercase English letters.

The length of S is an odd number between 3 and 99 (inclusive).

Input

Input is given from Standard Input in the following format:

S

Output

If S is a strong palindrome, print Yes;
otherwise, print No.

Sample Input 1

akasaka

Sample Output 1

Yes

S is akasaka.

The string formed by the 1-st through the 3-rd characters is aka.

The string formed by the 5-th through the 7-th characters is aka.
All of these are palindromes, so S is a strong palindrome.

Sample Input 2

level

Sample Output 2

No

Sample Input 3

atcoder

Sample Output 3

No

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

using System;
using System.Collections.Generic;
using System.Linq;

class Program
{
    static void Main(string[] args)
    {
        var input = Console.ReadLine().ToCharArray();

        var s1 = new char[(input.Length - 1) / 2];
        var s2 = new char[(input.Length - 1) / 2];
        Array.Copy(input, 0, s1, 0, (input.Length-1)/2);
        Array.Copy(input, (input.Length + 3)/2 - 1 , s2, 0, (input.Length-1)/2);

        for (int i = 0; i < input.Length; i++)
        {
            if (input[i] != input[input.Length - 1 - i])
            {
                Console.WriteLine("No");
                return;
            }

        }
        for (int i = 0; i < s1.Length; i++)
        {
            if (s1[i] != s1[s2.Length - 1 - i])
            {
                Console.WriteLine("No");
                return;
            }

        }
        for (int i = 0; i < s2.Length; i++)
        {
            if (s2[i] != s2[s2.Length - 1 - i])
            {
                Console.WriteLine("No");
                return;
            }

        }
        Console.WriteLine("Yes");
        

    }
}