#include <cmath>
#include <iostream>
using namespace std;
int main() {
	int N; string S;
	cin >> N >> S;
	bool found = false;
	for(int i = 1; i <= N; ++i) {
		if(N % i == 0) {
			bool flag = true;
			string sub = S.substr(0, i);
			for(int j = 0; j < N; j += i) {
				if(S.substr(j, i) != sub) {
					flag = false;
					break;
				}
			}
			if(flag) {
				int q_cnt = 0;
				for(int j = 0; j < i; ++j) {
					if(S[j] == 'H') flag = false;
					if(S[j] == 'Q') ++q_cnt;
				}
				if(q_cnt != N / i) flag = false;
			}
			if(flag) {
				cout << S.substr(0, i) << endl;
				found = true;
				break;
			}
		}
	}
	if(!found) {
		cout << -1 << endl;
	}
	return 0;
}