#include <iostream>
#include <stdio.h>
#include <math.h>
#include <string.h>
#include <time.h>
#include <stdlib.h>
#include <string>
#include <bitset>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <algorithm>
#include <sstream>
#include <stack>
#include <iomanip>
using namespace std;
#define pb push_back
#define mp make_pair
typedef pair<int,int> pii;
typedef long long ll;
typedef double ld;
typedef vector<int> vi;
#define fi first
#define se second
#define fe first
#define FO(x) {freopen(#x".in","r",stdin);freopen(#x".out","w",stdout);}
#define Edg int M=0,fst[SZ],vb[SZ],nxt[SZ];void ad_de(int a,int b){++M;nxt[M]=fst[a];fst[a]=M;vb[M]=b;}void adde(int a,int b){ad_de(a,b);ad_de(b,a);}
#define Edgc int M=0,fst[SZ],vb[SZ],nxt[SZ],vc[SZ];void ad_de(int a,int b,int c){++M;nxt[M]=fst[a];fst[a]=M;vb[M]=b;vc[M]=c;}void adde(int a,int b,int c){ad_de(a,b,c);ad_de(b,a,c);}
#define es(x,e) (int e=fst[x];e;e=nxt[e])
#define esb(x,e,b) (int e=fst[x],b=vb[e];e;e=nxt[e],b=vb[e])
ll T,a,b;
int main()
{
    cin>>T;
    while(T--) {
        cin>>a>>b;
        ll d=abs(a-b);
        ll l=1e18,r=-1e18;
        if(a==b) {
            l=min(l,2LL);
            r=max(r,a);
        }
        else {
            for(ll t=1;t*t<=d;++t) if(d%t==0) {
                ll u=d/t;
                auto upd=[&](ll x) {
                if(x>=2&&x<=max(a,b))
                    l=min(l,x),r=max(r,x);
                };
                upd(t); upd(u);
            }
        }
        if(l>r) l=r=-1;
        cout<<l<<" "<<r<<"\n";
    }
}
/*
c|a-b
c>=2
c<=max(a,b)
*/