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: Wrong Answer)

#include <stdint.h>
#include <algorithm>
#include <bitset>
#include <functional>
#include <iostream>
#include <string>
#include <vector>

bool check(std::string &s) {
  for(int i = 0; i <= s.size() / 2; i++){
    if(s[s.size() / 2 - i] != s[s.size() / 2 + i]) return false;
  }
  return true;
}

int main(int argc, char *argv[]) {
  std::string s;
  std::cin >> s;
  std::string s2 = s.substr(0, s.size() / 2);
  std::string s3 = s.substr(s.size() / 2 + 1, s.size() / 2);

  std::cout << ((check(s) && check(s2) && check(s3)) ? "Yes": "No") << std::endl;

  return 0;
}