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 <iostream>
#include <algorithm>
#include <string>
using namespace std;
typedef long long ll;


int main(void) {
	int n, i;
	string s;

	cin >> s;

	n = s.size();

	for (i = 0; i < n; i++) {
		if (s[i] != s[n - i - 1]) {
			cout << "No" << endl;
			return 0;
		}
	}

	for (i = 0; i < (n - 1) / 2; i++) {
		if (s[i] != s[(n - 1) / 2 - i - 1]) {
			cout << "No" << endl;
			return 0;
		}
	}

	for (i = (n + 1) / 2; i < n; i++) {
		if (s[i] != s[(n + 1) / 2 + n - 1 - i]) {
			cout << "No" << endl;
			return 0;
		}
	}

	cout << "Yes" << endl;

	return 0;
}