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

int t, a, b, s;

int read() {
    int x = 0, p = 1;
    char c = getchar();
    for (; !isdigit(c); c = getchar())
        if (c == '-') p = -1;
    for (; isdigit(c); c = getchar())
        x = (x << 3) + (x << 1) + (c & 15);
    return x * p;
}

int main() {
    t = read();
    while (t--) {
        a = read();
        b = read();
        s = abs(a - b);
        if (s == 0) {
            if (a == 1) puts("-1 -1");
            else cout << 2 << ' ' << a << endl;
            continue;
        }
        if (s == 1) {
            puts("-1 -1");
            continue;
        }
        for (int i = 2; i <= s; i++) {
            if (i * i > s) {
                cout << s << ' ';
                break;
            }
            if (s % i) continue;
            cout << i << ' ';
            break;
        }
        cout << s << endl;
    }
    return 0;
}