#include <bits/stdc++.h>
using namespace std;

#define rep(i,n) for(int i = 0; i < n; ++i)
using ll = long long;

int solve(void) {
	int N, K;
	cin >> N >> K;
	
	for(int x = N; x > K; --x) {
		bool flag = 1;
		for(int i = 2; i * i <= x and i <= K; ++i) {
			if(x % i == 0 and x / i <= K) {
				flag = 0;
				break;
			}
		}
		if(flag) {
			cout << x << endl;
			return 0;
		}
	}
	
	cout << -1 << endl;
	return 0;
}

int main(void) {
    int T;
    cin >> T;
    while(T--) solve();
    return 0;
}