#include<bits/stdc++.h> using namespace std; int t,n,k; int main() { cin>>t; while(t--) { cin>>n>>k; if(k%4==0 && n!=0) { cout<<-1<<endl; continue; } if(n==0) { cout<<0<<endl; continue; } n=4-n; k=k%4; if(n%2==1 && k%2==0) { cout<<-1<<endl; continue; } while(n%k!=0) { n+=4; } cout<<n/k<<endl; } return 0; }