#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

inline bool f(const int x, const int k) {
  for (int i = 1; i * i <= x; ++i) {
    if (x % i == 0) {
      if (i <= k && x / i <= k) return false;
    }
  }
  return true;
}

inline void solve() {
  int n, k;
  cin >> n >> k;
  for (int i = n; i >= max(1, n - 281); --i) {
    if (f(i, k)) {
      cout << i << "\n";
      return;
    }
  }
  cout << -1 << '\n';
}

int main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  int t;
  cin >> t;
  while (t--) solve();
  return 0;
}