#include <bits/stdc++.h>
using namespace std;
#include <atcoder/modint>
using namespace atcoder;
using mint = modint998244353;
using ll = long long;
#define fix(x) fixed << setprecision(x)
#define rep(i, n) for(int i = 0; i < n; ++i)
#define all(x) (x).begin(),(x).end()
template<class T>bool chmin(T&a, const T&b){if(a>b){a=b;return 1;}return 0;}
template<class T>bool chmax(T&a, const T&b){if(a<b){a=b;return 1;}return 0;}
constexpr ll INFLL = (1LL << 62), MOD = 998244353;
constexpr int INF = (1 << 30);

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int t;
    cin >> t;
    while(t--){
        ll n,k;
        cin >> n >> k;
        for(;n>k;--n){
            bool ok = true;
            for(int j=1;j*j<=n&&ok;++j){
                if(!(n%j) && n/j<=k) ok = false;
            }
            if(ok) break;
        }
        if(n<=k) n = -1;
        cout << n << '\n';
    }
    return 0;
}