#include<bits/stdc++.h>
using namespace std;
using ll = long long int;
using ld = long double;
#define pow(n,m) powl(n,m);
#define sqrt(n) sqrtl(n);
const ll MAX = 5000000000000000000;
const ll MOD = 1000000007;
//998244353;
void randinit(){srand((unsigned)time(NULL));}
int main(){
    ll N,q = 0;
    string S;
    cin >> N >> S;
    for(ll i = 0;i < N;i++){
        if(S[i] == 'H'){
            cout << -1 << endl;
            return 0;
        }
        if(S[i] == 'Q'){
            q++;
        }
    }
    vector<ll> Y(0);
    for(ll i = 1;i <= N;i++){
        if(N % i == 0){
            ll p = 0;
            for(ll j = 0;j < i;j++) if(S[j] == 'Q') p++;
            if(p * i == N){
                bool ok = 1;
                for(ll j = 0;j < N;j++){
                    if(S[j] != S[j % i]){
                        ok = 0;
                    }
                }
                if(ok){
                    for(ll j = 0;j < i;j++){
                        cout << S[j];
                    }
                    cout << endl;
                    return 0;
                }
            }
        }
    }
    cout << -1 << endl;
}