#include <bits/stdc++.h>
using namespace std;
using Int = long long;
constexpr static int mod = 1e9 + 7;
constexpr static int inf = (1 << 30) - 1;
constexpr static Int infll = (1LL << 61) - 1;
int Competitive_Programming = (ios_base::sync_with_stdio(false), cin.tie(nullptr), cout << fixed << setprecision(15), 0);
#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")

int main()
{
	int N;
	cin >> N;
	string s;
	cin >> s;

	for (int i = 0; i < N; i++)
	{
		assert(('A' <= s[i] and s[i] <= 'Z') or ('a' <= s[i] and s[i] <= 'z'));
		if (s[i] != 'Q')
		{
			cout << -1 << "\n";
			return 0;
		}
	}

	for (int i = 0; i * i <= N; i++)
	{
		if (i * i == N)
		{
			for (int j = 0; j < i; j++)
			{
				cout << "Q";
			}

			cout << "\n";

			return 0;
		}
	}

	cout << -1 << "\n";
}