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)


// Problem : B - String Palindrome
// Contest : AtCoder Beginner Contest 159
// URL : https://atcoder.jp/contests/abc159/tasks/abc159_b
// Memory Limit : 1024 MB
// Time Limit : 2000 ms
// Powered by CP Editor (https://github.com/cpeditor/cpeditor)

#include <bits/stdc++.h>

using namespace std;

bool isPal(string s){
	int len = s.size();
	for(int i = 0; i < len / 2; i++)
		if (s[i] != s[len - i - 1]){
			return false;
		}
	return true;
}
int main(){
	string s;
	cin >> s;
	int len = s.size();
	
	if (isPal(s) && isPal(s.substr(0,(len - 1) / 2)) && isPal(s.substr((len + 3)/2-1))){
		cout << "Yes" << endl;
	}else {
		cout << "No" << endl;
	}
	
	
	return 0;	
}