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: Accepted)

#include<bits/stdc++.h>
using namespace std;
bool ispalin(string s){
    int len = s.length();
    bool flag = true;
    for(int i=0; i<len/2; i++){
        if(s[i]!=s[len-1-i]){
            flag = false;
            break;
        }
    }
    return flag;
}
int main(){
    string s;
    cin >> s;
    int len = s.length();
    string part1 = s.substr(0, (len-1)/2), part2 = s.substr((len+1)/2, (len-1)/2);
    if(ispalin(s) and ispalin(part1) and ispalin(part2))
        cout << "Yes";
    else
        cout << "No";
    return 0;
}