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++14 (GCC 5.4.1) (judge verdict: Accepted)

#pragma GCC optimize("Ofast,inline,unroll-loops,fast-math")
#include <iostream>
#include <algorithm>
#include <cstdio>
#include <string>
using namespace std;

bool Check(string a)
{
    int i, j;

    for(i = 0, j = (signed)a.size() - 1; i < j; i ++, j --)
        if(a[i] != a[j])
            return false;

    return true;
}

int main(void)
{
    string a;

    cin >> a;
    cout << (Check(a) && Check(a.substr(0, (a.size() - 1) / 2)) && Check(a.substr((a.size() + 3) / 2 - 1, a.size() - (a.size() + 3) / 2 + 1)) ? "Yes" : "No") << endl;

    return 0;
}