CF 1389A

#include <bits/stdc++.h>
using namespace std;
#define test int t; cin>>t; while (t--)
#define ll long long int
#define fellow_junior  ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
int main()
{
   fellow_junior

   test
   {
       ll a,c,d,e,f,i,j;
       cin>>a>>c;
       if(a*2>c)
       {
           cout<<-1<<" "<<-1<<endl;
       }
       else
       {
           cout<<a<<" "<<2*a<<endl;
       }
   }

   return 0;
}