#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
ll n,m;
map <int ,queue <int> > q;
int a[555];
inline bool JudgePrime(ll digit) {
    if(digit==2 || digit==3)return true;
    else if(digit<=1 || digit%2==0)return false;
    else if(digit>3) {
        for(int i=3; i*i<=digit; i+=2)if(digit%i==0)return false;
        return true;
    }
}
int main()
{
    int t;
    cin>>t;
    while(t --){
        cin>>n>>m;
        if(n==m){
            if(n==1) {
                cout<<"-1 -1"<<'\n';
            }else {
                cout<<"2 "<<m<<'\n';
            }    
            continue;
        }
        else if(m%2==n%2){
                cout<<"2 "<<abs(m-n)<<'\n';
            }
        else if(abs(n-m)==1){
            cout<<"-1 -1"<<'\n';
        }
        else if(JudgePrime(abs(n-m))){
            cout<<abs(n-m)<<' '<<abs(n-m)<<'\n';
            }
        else {
            for(int i=3;i<=abs(n-m);i+=2){
                if(n%i==m%i) {
                    cout<<i<<' '<<abs(n-m)<<'\n';
                    break;
                }
            }
        }
        
            
    }

}