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

int main() {
    int N;
    string S;
    cin >> N >> S;
    if(S[N-1] == 'Q') {
        cout << S.substr(0,N-1) << 'Q' << endl;
    }
    else {
        cout << -1 << endl;
    }
}