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 <algorithm>
#include <bits/stdc++.h>
#include<iostream>
#include<string>
using namespace std;
#define rep(i, n) for (int i = 0; i <(int)(n); i++)
#define all(x) (x).begin(), (x).end()
#define ll long long
const int INF=1000100010;
int main(){
string s;
string down,up;
cin>>s;
int n=s.size();
down=s.substr(0,(n-1)/2);
up=s.substr((n+3)/2-1,(n-1)/2);
string down1=down;
string up1=up;
reverse(all(down));
reverse(all(up));
if(down==down1&&up==up1)cout<<"Yes"<<endl;
else cout<<"No"<<endl;
}