#include <bits/stdc++.h>
using namespace std;

int main() {
    string S;
    cin >> S;
    int N = S.size();
    string s1 = S.substr(0, N / 2);
    string s2 = S.substr(N / 2 + 1, N / 2);
    if (s1 == s2) cout << "Yes" << endl;
    else cout << "No" << endl;
}
