#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int INF = 1e9 + 10;
const ll INFL = 4e18;

int main() {
    int T;
    cin >> T;

    while (T--) {
        ll N, M;
        cin >> N >> M;

        const ll mod = 1e9;
        N %= mod, M %= mod, (M = mod - M) % M;

        if (M == N) {
            cout << 1 << '\n';
        } else if (N == 0 || M % N) {
            cout << -1 << '\n';
        } else {
            cout << M / N << '\n';
        }
    }
}