#include <bits/stdc++.h>

using namespace std;

void fast_io() {
	ios::sync_with_stdio(false);
	std::cin.tie(nullptr);
}

int main() {
	fast_io();
	const int M = 1e7 + 5;
	vector<bool> is_prime(M, true);
	vector<int> primes;
	is_prime[0] = is_prime[1] = false;
	for (int i = 2; i < M; i++) {
		if (is_prime[i]) {
			primes.push_back(i);
			for (long long j = 1LL * i * i; j < M; j += i) {
				is_prime[j] = false;
			}
		}
	}
	vector<long long> good_nums;
	for (int i = 0; i < primes.size() - 1; i++) {
		if (primes[i + 1] - primes[i] == 2) {
			good_nums.push_back(1LL * primes[i] * primes[i + 1]);
		}
	}
	int q;
	cin >> q;
	for (; q--;) {
		long long n;
		cin >> n;
		auto it = lower_bound(good_nums.begin(), good_nums.end(), n + 1);
		if (it == good_nums.begin()) {
			cout << "-1\n";
		} else {
			--it;
			cout << *it << "\n";
		}
	}
}