#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>
#include<fstream>
using namespace std;
int main() {
	int n;
	string s;
	cin >> n >> s;
	if (s[n - 1] == 'Q') {
		cout << s << endl;
	}
	else {
		cout << -1 << endl;
	}
}