#include<bits/stdc++.h>
using namespace std;
int main(){
//	freopen("math.in","r",stdin);
//	freopen("math.out","w",stdout);
	int n;
	cin>>n;
	int x,z;
	for(int i=0;i<n;i++){
		bool b=0;
		cin>>x>>z;
		if(z%x){cout<<"-1"<<endl;continue;}
		if(z/x%x==0){cout<<"-1"<<endl;continue;}
		for(int j=1;j<=10000;j++){
			if(x*j*__gcd(x,j)==z){cout<<j<<endl;b=1;break;}
		}
		if(!b)cout<<"-1"<<endl;
	}
}

（本人很菜，见谅）