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 rep(i,n) for (int i=0;i<(n);i++)
#define adrep(i,s,n) for (int i=(s);i<(n);i++)
using namespace std;
typedef long long ll;

int check(string t){

  int n=t.length();
  rep(i,n){
    //cout<<t[i]<<" "<<t[n-(i+1)]<<endl;
    if(t[i]!=t[n-(i+1)]){
      return 0;
    }
  }
  return 1;
}

int main(){

 string s;
  
  cin>>s;
  
  int N=s.length();
  
  if(check(s)==0){cout<<"No"<<endl;return 0;}
  string s1=s.substr(0,(N-1)/2);
  //cout<<s1<<endl;
  if(check(s1)==0){cout<<"No"<<endl;return 0;}
  string s2=s.substr((N+3)/2-1,(N-1)/2);
  //cout<<s2<<endl;
  if(check(s2)==0){cout<<"No"<<endl;return 0;}
  
  cout<<"Yes"<<endl;
}