#include <bits/stdc++.h>
#define For(i,l,r) for (register int i=l; i<=r; i++)
using namespace std;
typedef unsigned long long LL;
typedef signed long long ll;
#define int ll
template <typename T>
inline void read(T &x) {
    char c = getchar(); int w = 1; x = 0;
    while (!isdigit(c))
        (c == '-') && (w = -w), c = getchar();
    while (isdigit(c))
        x = (x << 1) + (x << 3) + (c ^ '0'), c = getchar();
    x *= w;
}

int T, a, b;
signed main() {
    read(T);
    while (T -- > 0) {
        read(a); read(b);
        if (a == b) {
            if (a == 1) puts("-1 -1");
            else cout << 2 << " " << a << endl; continue;
        }
        if (a < b) swap(a, b);
        int mi = a, mx = 1;
        for (register int i=1; i*i<=a-b; ++i) {
            if ((a-b) % i == 0) {
                if (a/i-b/i == (a-b)/i && i > 1) {
                    mi = min(mi, i);
                    mx = max(mx, i);
                }
                int x = (a-b)/i;
                if (a/x-b/x == (a-b)/x && x > 1) {
                    mi = min(mi, x);
                    mx = max(mx, x);
                }
            }
        }
        if (mi == a) {
            puts("-1 -1");
        }
        else {
            printf("%d %d\n", mi, mx);
        }
    }
    getchar();
    return 0;
}