#include <iostream>
#include <string>

using namespace std;
int main(){
    int i,n; cin >> n;
    string s; cin >> s;
    int cnt = 0;
    for(i=0;i<n;i++){
        if(s[i]=='H'){
            cout << -1 << endl;
            return 0;
        }
        if(s[i]=='Q') cnt++;
    }
    if(cnt>=2 || cnt==0) cout << -1 << endl;
    else cout << s << endl;
}