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 <iostream>
using namespace std;
#define int long long
signed main() {
	string s;
	cin>>s;
	int n=s.size();
	int i=0;
	int j=s.size()-1;
	while(i<j)
	{
	    if(s[i]!=s[j])
	    break;
	    i++;
	    j--;
	}
	if(i!=j)
	{
	    cout<<"No"<<endl;
	    return 0;
	}
	j=(n-1)/2-1;
	i=0;
	while(i<j)
	{
	    if(s[i]!=s[j])
	    {
	        cout<<"No";
	        return 0;
	    }
	    i++;
	    j--;
	}
	cout<<"Yes";
}