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>
using namespace std;
#define rep(i,n) for(int i=0;i<n;i++)
#define ll long long
#define vec_rep(itr,v) for(auto itr = v.begin(); itr != v.end(); ++itr)

int main(void){
    string S;
    cin >> S;
    int S_len = (int)S.size();
    string S1,S2,S1_r,S2_r;
    S1 = S.substr(0,(S_len-1)/2);
    S2 = S.substr((S_len+1)/2);
    S1_r = S1;
    reverse(S1_r.begin(),S1_r.end());
    S2_r = S2;
    reverse(S2_r.begin(),S2_r.end());
    if(S1 == S1_r && S2 == S2_r)cout << "Yes" << endl;
    else cout << "No" << endl;
    return 0;
}