#include <bits/stdc++.h>
using namespace std;

int a, b;
int mi, ma;

void check(int x) {
    if (x < 2 || x > max(a, b)) return;
    if (a % x == b % x) mi = min(mi, x), ma = max(ma, x);
}

void work() {
    scanf("%d%d", &a, &b);
    mi = a + b;
    ma = 0;
    for (int i = 1; i <= a; ) {
        check(i);
        check(i + 1);
        i = a / (a / i) + 1;
    }    
    
    for (int i = 1; i <= b; ) {
        check(i);
        check(i + 1);
        i = b / (b / i) + 1;
    }
    check(a);
    check(b);
    check(2);
    check(a - b);
    check(b - a);
    if (mi > ma) puts("-1 -1");
    else printf("%d %d\n", mi, ma);
}

int main() {
    int T;
    scanf("%d", &T);
    while (T--) work();
}