#include<bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define SZ(x) ((int)x.size())
#define ALL(x) x.begin(),x.end()
#define L(i,u) for (int i=head[u]; i; i=nxt[i])
#define rep(i,a,b) for (int i=(a); i<=(b); i++)
#define per(i,a,b) for (int i=(a); i>=(b); i--)
typedef long double ld;
typedef long long ll;
typedef unsigned int ui;
typedef pair<int,int> Pii;
typedef vector<int> Vi;
template<class T> inline void read(T &x){
    x=0; char c=getchar(); int f=1;
    while (!isdigit(c)) {if (c=='-') f=-1; c=getchar();}
    while (isdigit(c)) {x=x*10+c-'0'; c=getchar();} x*=f;
}
template<class T> T gcd(T a, T b){return !b?a:gcd(b,a%b);}
template<class T> inline void umin(T &x, T y){x=x<y?x:y;}
template<class T> inline void umax(T &x, T y){x=x>y?x:y;}
template<class T> inline T Abs(const T &x){return x>0?x:-x;}
inline ui R() {
    static ui seed=416;
    return seed^=seed>>5,seed^=seed<<17,seed^=seed>>13;
}
// const int N = ;
int l,r;
void upd(int x){
    if(x>r)r=x;
    if(x<l||l==-1)l=x;
}
int main() {
    int T;read(T);while(T--){
        int a,b;cin>>a>>b;if(a>b)swap(a,b);//a<=b
        a=Abs(a-b);
        l=-1,r=-1;
        for(int x=1;x*x<=a;x++)if(a%x==0){
            if(a/x>1)upd(a/x);if(x>1)upd(x);
        }
        if(!a)l=2<=b?2:-1,r=b>1?b:-1;
        printf("%d %d\n",l,r);
    }
    return 0;
}