#include<bits/stdc++.h>
using namespace std;
int main(){
  string s;
  cin >> s;
  int n = s.size();
  int m = (n-1)/2;
  int flag = 0;
  for(int i;i<m;i++){
    if(s.at(i)!=s.at(i+m+1)){
      flag += 1;
    }
  }
  if(flag==0){
    cout << "Yes" << endl;
  }else{
    cout << "No" << endl;
  }
}