// Skyqwq
#include <iostream>
#include <cstdio>
#define pb push_back
#define fi first
#define se second
#define mp make_pair

using namespace std;

typedef long long LL;

template <typename T> void chkMax(T &x, T y) { if (y > x) x = y; }
template <typename T> void chkMin(T &x, T y) { if (y < x) x = y; }

template <typename T> void inline read(T &x) {
    int f = 1; x = 0; char s = getchar();
    while (s < '0' || s > '9') { if (s == '-') f = -1; s = getchar(); }
    while (s <= '9' && s >= '0') x = x * 10 + (s ^ 48), s = getchar();
    x *= f;
}
 
int mx = -2e9, mn = 2e9;

int a, b;

void inline chk(int x) {
    if (x <= 1 || x > max(a, b)) return;
    chkMin(mn, x);
    chkMax(mx, x);
}

int main() {
    int T; read(T);
    while (T--) {
        mx = -2e9, mn = 2e9;
        read(a), read(b);
        int n = abs(a - b);
        if (a == 1 && b == 1) {
            puts("-1 -1");
            continue;
        }
        if (a == b) {
            printf("%d %d\n", 2, a);
            continue;
        }
        for (int i = 1; i * i <= n; i++) {
            if (n % i == 0) {
                chk(i);
                chk(n / i);
            }
        }
        if (mn == 2e9) puts("-1 -1");
        else printf("%d %d\n", mn, mx);
    }
    return 0;
}