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>
using namespace std;
using p=pair<int,int>;
#define int long long
#define rep(i,N) for(int i=0;i<N;i++)

signed main(){
  string S;
  cin>>S;
  int N=S.size();
  int N2=(N-1)/2;
  int N3=(N+3)/2;
  
  string N2st="";
  rep(i,N2)N2st=N2st+S[i];
  string N3st="";
  rep(N3,N)N3st=N3st+S[N3];
  
  string Srev=S;
  reverse(S.begin(),S.end());
  string N2strev=N2st;
  reverse(N2st.begin(),N2st.end());
  string N3strev=N3st;
  reverse(N3st.begin(),N3st.end());
  
  string ans="No";
  if(S==Srev&&N2st==N2strev&&N3st==N3strev)ans="Yes";
  cout<<ans<<endl;
}