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)

#include <bits/stdc++.h>
using namespace std;

int main() {
    string s;
    int i;
    cin >> s;
    int leng = s.length(), small = (leng - 1)/2, big = (leng + 3)/2;
    for(i = 0; i < s.length()/2 - 1; i++){
        if(s.at(i) != s.at(leng-i-1)){
            cout << "No" << endl;
            return 0;
        }
    }
    for(i = 0; i < small/2 - 1; i++){
        if(s.at(i) != s.at(small-i-1)){
            cout << "No" << endl;
            return 0;
        }
    }
    for(i = 0; i < (leng-big+1)/2; i++){
        if(s.at(big+i-1) != s.at(leng-i-1)){
            cout << "No" << endl;
            return 0;
        }
    }
    cout << "Yes" << endl;
}