#include <iostream>
using namespace std;
int main() {
    string S;
    bool M = 0;
    cin >> S;
    int N = S.size();
    for (int i = 0; i < N/2; i++){
        if(S.at(i) != S.at(i+(N/2)+1)){
        M =1;
        break;
        }
    }
    if(M)cout << "No" << endl;
    else cout << "Yes" << endl;
}