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;
#define rep(i, n) for (int i = 0; i < n; i++)

int main(){
	string s;
	cin >> s;
	
	bool equal = true;
	rep(i, s.size()) {
		if (s.at(i) != s.at(s.size() - i - 1)) {
		equal = false;
		}
	}
  //cout << equal << endl;
	rep(i, (s.size()-1)/2) {
		if (s.at(i) != s.at((s.size()+1)/2+i)) {
			equal = false;
		}
      //cout << equal << endl;
	}
	
	if (equal) {
		cout << "Yes" << endl;
	} else {
		cout << "No" << endl;
	}
}