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>
#define F first
#define S second
#define PB push_back
#define MP make_pair

using namespace std;

typedef long long ll;
typedef vector<int> vi;
typedef pair<int , int> pi;

bool ispal(string s, int l, int r)
{
	bool y = true;
	while(l<r) {
		if(s[l++] != s[r--]) {
			y = false;
			break;
		}
	}
	return y;
}
	
int main()
{
	ios::sync_with_stdio(0);
	cin.tie(0);
	string s;
	cin>>s;
	int n = s.size();
	bool y = true;
	if(!ispal(s, 0, n-1))
		y = false;
	if(!ispal(s, 0, (n-2)/2))
		y = false;
	if(!ispal(s, (n+2)/2, n-1))
		y = false;
	if(y)
		cout<<"Yes\n";
	else
		cout<<"No\n";
	
	return 0;
};