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;

using lli = long long int;

template <class T>ostream &operator<<(ostream &o,const vector<T>&v)
{o<<"{";for(int i=0;i<(int)v.size();i++)o<<(i>0?", ":"")<<v[i];o<<"}";return o;}

template <class T>ostream &operator<<(ostream &o,const pair<T, T>&p)
{o<<"("<<p.first<<", "<<p.second<<")";return o;}

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

bool palcheck(string s){
    int n = s.size();
    if(n <= 1) return true;

    rep(i, n/2){
        if(s[i] != s[n-i-1]) return false;
    }
    return true;
}

string s;

int main(void){
    cin >> s;
    int nl, nr;
    nl = s.size()/2;
    nr = nl+1;
    string sl, sr;
    sl = s.substr(0, nl);
    sr = s.substr(nr, nl);
    if(palcheck(sl) && palcheck(sr)) cout << "Yes" << endl;
    else cout << "No" << endl;
    return 0;
}