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++ (GCC 9.2.1) (judge verdict: Accepted)

#include<bits/stdc++.h>
using namespace std;
int main()
{
    int n,m,p;
    string s1,s2,s3,s4,s5,s6;
    cin>>s1;
    n=s1.length();
    m=(n+2)/2;
    p=(n-1)/2;
    s2=string(s1.rbegin(),s1.rend());
    if(s1.compare(s2)==0)
    {
        s4=string(s1.begin(),s1.begin()+p);
        s3=string(s1.rbegin()+m,s1.rend());

        if(s3.compare(s4)==0)
        {
            s5=string(s1.begin()+m,s1.end());
            s6=string(s1.rbegin(),s1.rbegin()+p);


            if(s5.compare(s6)==0)
            {
                cout<<"Yes"<<endl;
            }
            else
            {
                cout<<"No"<<endl;
            }
        }
        else
        {
            cout<<"No"<<endl;
        }
    }
    else
    {
        cout<<"No"<<endl;
    }
    return 0;

}