#include <bits/stdc++.h>
using namespace std;
#define int long long
#define db double
#define gcd(a,b) __gcd(a,b)
#define lcm(a,b) a*b / __gcd(a,b)
#define I first
#define II second
#define pb push_back
#define ii pair<int,int>
const int INF = 2 * 1e18;
const int N = 3e5 + 1;
const int MOD = 1e9 + 7;    
int n, k;
int ok(int n) {
    for (int i = 2; i * i <= n && i <= k; i++) 
        if (n % i == 0 && i <= k && n / i <= k) return 0;
    return 1;
}
void solve() {
    cin >> n >> k;
    for (int i = n; i > k; i--) 
        if (ok(i)) {
            cout << i << '\n';
            return ;
        }
    cout << -1 << '\n';
}
int32_t main()
{
    #define TASKNAME "test"
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    if (fopen(TASKNAME ".inp","r" ))
    {
        freopen(TASKNAME ".inp","r",stdin);
        freopen(TASKNAME ".out","w",stdout);
    }
    int t = 1; 
    cin >> t;
    while (t--) solve();
    return 0;
}