#include <bits/stdc++.h>

#define rep(i, n) for (int i = 0; i < (n); i++)

using namespace std;

int main() {
    int n;
    string s;
    cin >> n >> s;

    int m = round(sqrt(n));
    cout << (s == string(n, 'Q') and m * m == n ? string(m, 'Q') : "-1") << endl;

    return 0;
}