#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <iomanip>
#include <cmath>
#include <stdio.h>
#include <queue>
#include <deque>
#include <cstdio>
#include <set>
#include <map>
#include <bitset>
#include <stack>
#include <cctype>
using namespace std;
int main() {
	int n;
	string s;
	cin >> n >> s;
	if (s[n - 1] != 'Q') {
		cout << -1 << endl;
		return 0;
	}
	for (int i = 0; i < s.size(); i++) {
		if (s[i] == 'H') {
			cout << -1 << endl;
			return 0;
		}
	}
	for (int i = 1; i <= n; i++) {
		if (n % i == 0) {
			set<string> st;
			for (int j = 0; j < n; j += i) {
				st.insert(s.substr(j, i));
			}
			if (st.size() == 1) {
				string s1 = *st.begin();
				int co = 0;
				for (int j = 0; j < s1.size(); j++) {
					if (s[j] == 'Q') {
						co++;
					}
				}
				if (co == n / i) {
					cout << s1 << endl;
					return 0;
				}
			}
		}
	}
	cout << -1 << endl;
}