#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, s, t) for (ll i = s; i < (ll)(t); i++)
#define all(x) begin(x), end(x)

template <class T> bool chmin(T& x, T y) {
	return x > y ? (x = y, true) : false;
}
template <class T> bool chmax(T& x, T y) {
	return x < y ? (x = y, true) : false;
}

struct io_setup {
	io_setup() {
		ios::sync_with_stdio(false);
		cin.tie(nullptr);
		cout << fixed << setprecision(15);
	}
} io_setup;

long long isqrt(long long n) {
	if (n <= 0) return 0;
	long long x = sqrt(n);
	while ((x + 1) * (x + 1) <= n) x++;
	while (x * x > n) x--;
	return x;
}

void solve() {
	int n, k;
	cin >> n >> k;
	auto check = [&](int x) {
		int qx = isqrt(x);
		chmin(qx, k);
		while (1) {
			if (x % qx == 0) {
				return (x / qx > k);
			}
			qx--;
		}
		return false;
	};
	while (n > k) {
		if (check(n)) {
			cout << n << "\n";
			return;
		}
		n--;
	}
	cout << "-1\n";
}

int main() {
	int t = 1;
	cin >> t;
	while (t--) solve();
}