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 <iostream>
# include <string>
# include <algorithm>

using namespace std;


bool palindrome1 (string s) {
    string ss = s.substr(0, (s.size()-1)/2);
    string ss_ = ss;
    reverse(ss_.begin(), ss_.end());
    return ss == ss_;
}


bool palindrome2 (string s) {
    int cursor = (s.size()+3)/2 - 1;
    string ss = s.substr(cursor, s.size()-cursor);
    string ss_ = ss;
    return ss == ss_;
}


int main () {
    string s; cin >> s;

    if (palindrome1(s)) cout << "Yes" << endl;
    else cout << "No" << endl;
    return 0;
}