#include <iostream>
#include <cstring>
#include <cstdio>
#include <algorithm>
#include <cmath>

using namespace std;
const int maxn = 500010, inf = 1e9 + 233;

template <typename T>
inline void read(T &k)
{
    int f = 1; k = 0; char c = getchar();
    while (c < '0' || c > '9') c == '-' && (f = -1), c = getchar();
    while (c <= '9' && c >= '0') k = k * 10 + c - '0', c = getchar();
    k *= f;
}

void solve()
{
    int a, b;
    read(a); read(b);
    if (a == b && (a != 1 || b != 1))
    {
        printf("%d %d\n", 2, a);
        return;
    }
    int tmp = abs(b - a);
    int ans1 = -1, ans2 = -1;
    for (int i = 2; 1ll * i * i <= tmp; i++)
    if (tmp % i == 0)
    {
        ans1 = i;
        break;
    }

    if (ans1 == -1 && tmp > 1)
        ans1 = tmp;

    printf("%d %d\n", ans1, abs(b - a) > 1 ? abs(b - a) : -1);
}

int main()
{
    int T;
    read(T);
    while (T--)
        solve();
}