#include<bits/stdc++.h>
#include<atcoder/all>
#define rep(i,n) for(int i=0;i<n;i++)
using namespace std;
using namespace atcoder;
typedef long long ll;
typedef vector<int> vi;
typedef vector<long long> vl;
typedef vector<vector<int>> vvi;
typedef vector<vector<long long>> vvl;
typedef long double ld;
typedef pair<int, int> P;

template <int m> ostream& operator<<(ostream& os, const static_modint<m>& a) {os << a.val(); return os;}
template <int m> ostream& operator<<(ostream& os, const dynamic_modint<m>& a) {os << a.val(); return os;}
template <int m> istream& operator>>(istream& is, static_modint<m>& a) {long long x; is >> x; a = x; return is;}
template <int m> istream& operator>>(istream& is, dynamic_modint<m>& a) {long long x; is >> x; a = x; return is;}
template<typename T> istream& operator>>(istream& is, vector<T>& v){int n = v.size(); assert(n > 0); rep(i, n) is >> v[i]; return is;}
template<typename U, typename T> ostream& operator<<(ostream& os, const pair<U, T>& p){os << p.first << ' ' << p.second; return os;}
template<typename T> ostream& operator<<(ostream& os, const vector<T>& v){int n = v.size(); rep(i, n) os << v[i] << (i == n - 1 ? "\n" : " "); return os;}
template<typename T> ostream& operator<<(ostream& os, const vector<vector<T>>& v){int n = v.size(); rep(i, n) os << v[i] << (i == n - 1 ? "\n" : ""); return os;}
template<typename T> ostream& operator<<(ostream& os, const set<T>& se){for(T x : se) os << x << " "; os << "\n"; return os;}
template<typename T> ostream& operator<<(ostream& os, const unordered_set<T>& se){for(T x : se) os << x << " "; os << "\n"; return os;}
template<typename S, auto op, auto e> ostream& operator<<(ostream& os, const atcoder::segtree<S, op, e>& seg){int n = seg.max_right(0, [](S){return true;}); rep(i, n) os << seg.get(i) << (i == n - 1 ? "\n" : " "); return os;}
template<typename S, auto op, auto e, typename F, auto mapping, auto composition, auto id> ostream& operator<<(ostream& os, const atcoder::lazy_segtree<S, op, e, F, mapping, composition, id>& seg){int n = seg.max_right(0, [](S){return true;}); rep(i, n) os << seg.get(i) << (i == n - 1 ? "\n" : " "); return os;}

template<typename T> void chmin(T& a, T b){a = min(a, b);}
template<typename T> void chmax(T& a, T b){a = max(a, b);}


template<typename T>
T pow_mod(T A, T N, T MOD){
	T res = 1 % MOD;
	A %= MOD;
	while(N){
		if(N & 1) res = (res * A) % MOD;
		A = (A * A) % MOD;
		N >>= 1;
	}
	return res;
}

const long long e9 = 1000000000;

long long solve(long long n, long long m, long long MOD){
	long long g = gcd(MOD, n);
	if(g >= 2){
		if(m % g == 0) return solve(n / g, m /g, MOD / g);
		else return -1LL;
	}
	long long phi = MOD;
	if(MOD % 2 == 0) phi /= 2;
	if(MOD % 5 == 0){
		phi /= 5;
		phi *= 4;
	}
	long long n_inv = pow_mod(n, phi - 1, MOD);
	long long ans = (((-m % MOD) + MOD) * n_inv) % MOD;
	if(ans == 0) ans += MOD;
	return ans;
}

int solve(){
	long long n, m;
	cin >> n >> m;
	
	cout << solve(n, m, e9) << "\n";
	return 0;
};

int main(){
	int t;
	cin >> t;
	rep(_, t) solve();
	return 0;
}