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 <bits/stdc++.h>
    #define rep(i,n) for(int i = 0; i < (n); i++)
     
    using namespace std; 
    using ll = long long;
    using P = pair<int,int>; 
    
    int main() {
     string s;
     cin >> s;
     int n = s.size();
     string str1 = s.substr(0,(n-1)/2);
     string str2 = s.substr((n+3)/2-1,n-1);
     string str3 = str1;
     string str4 = str2;
     reverse(str1.begin(),str1.end());
     reverse(str2.begin(),str2.end());
     
     if(str1 == str3 && str2 == str4)	cout << "Yes" << '\n';
     else cout << "No" << '\n';
    
     return 0;
    }