#pragma GCC optimize("O3")
#include <iostream>
#include<string>
#include<string.h>
#include<cstring>
#include<iomanip>
#include<algorithm>
#include<string>
#include<list>
#include<string.h>
#include<vector>
#include<math.h>
#include<cmath>
#include<stdlib.h>
#include<set>
#include<map>
#include<fstream>
#include<unordered_map>
#include<cstring>
#include<stack>
#include<unordered_set>
#include<queue>
using namespace std;
#define ri register signed
#define RI register signed
#define cf cout.flush();
#define lson (rt<<1|1)
#define rson (rt<<1)
#define lson1 (rt1<<1)
#define rson1 (rt1<<1|1)
#define lson2 (rt2<<1)
#define rson2 (rt2<<1|1)
#define mid ((l+r)>>1)
#define mid1 ((l1+r1)>>1)
#define mid2 ((l2+r2)>>1)
#define mes(x) memset(x,0,sizeof x)
typedef long long LL;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll, ll> pll;
typedef pair<signed, signed>P;
typedef pair<signed, P> PP;
typedef pair<int, pll> PPll;
//#define int long long
//#define double long double
#define ri register signed
#define il inline
#define deb(...) logger(#__VA_ARGS__,__VA_ARGS__)
template<typename ...Args>
void logger(string vars, Args&&... values)
{
    cout << vars << " = ";
    string delim = "";
    //(..., (cout << delim << values, delim = ", "));
}
inline string toString(int x)
{
    string ans = "";
    bool negtive = x < 0;
    x = abs(x);
    while (x)ans.push_back(x % 10 + '0'), x /= 10;
    if (ans.size() == 0)ans = "0";
    if (negtive)ans.push_back('-');
    for (int i = 0; i < ans.size() / 2; i++)
        swap(ans[i], ans[ans.size() - 1 - i]);
    return ans;
}
inline int toInt(const string&str)
{
    int ans = 0;
    bool negtive = str[0] == '-';
    for (int i = negtive; i < str.size(); i++)
        ans = ans * 10 + str[i] - '0';
    if (negtive)ans *= -1;
    return ans;
}
inline int gcd(int x, int y) { return x ? gcd(y%x, x) : y; }
ll exgcd(ll a, LL b, LL &x, LL &y) {
    LL d = a; if (b == 0) x = 1, y = 0; else {
        d = exgcd(b, a%b, y, x), y -= a / b * x;
    }
    return d;
}

const int mod = 998244353;
inline int read() {
    int ans = 0; char last = ' ', ch = getchar();
    while (!(ch >= '0' && ch <= '9'))last = ch, ch = getchar();
    while (ch >= '0' && ch <= '9')ans = (ans << 3) + (ans << 1) + ch - '0', ch = getchar();
    return ans;
}
inline int QPow(ll a, ll b) {
    LL ans = 1;
    if (b < 0)return 0;
    while (b) {
        if (b & 1)ans = ans * a; a = a * a; b >>= 1;
    }
    return ans;
}
inline int QPow(LL  a, LL b, const int&mod) {
    LL ans = 1;
    while (b) {
        if (b & 1)ans = ans * a%mod; a = a * a%mod; b >>= 1;
    }
    return ans;
}
const double PI = 3.141592653589793115997963468544185161590576171875;
const double e = 2.718281828459045;
void ask(int x)
{
    cout << '?' << ' ' << x << endl;
    cf;
}
void decide(int x)
{
    cout << "! " << x << endl;
    cf;
}
short _min(short a, short b)
{
    return a < b ? a : b;
}
const int inf = 1+(1 << 30);
const int inf2 = 10000;
const double eps = 1e-10;
int db_cmp(double x, double y)
{
    if (fabs(x - y) < eps)return 0;
    if (x > y)return 1;
    return -1;
}
double distance(P p1, P p2)
{
    return sqrt((p1.first - p2.first)*(p1.first - p2.first) +
        (p2.second - p1.second)*(p2.second - p1.second));
}
const int maxn = 400002;

LL inv[maxn];
LL fac[maxn], fac_1[maxn];
LL QPow(LL a, LL b, LL md)
{
    LL ans = 1;
    while (b)
    {
        if (b & 1)ans = ans * a%md;
        a = a * a%md;
        b >>= 1;
    }
    return ans;
}
void getInv()
{
    inv[1] = 1;
    for (int i = 2; i < maxn; i++)
        inv[i] = (mod - mod / i)*inv[mod%i] % mod;
}
void init()
{
    fac[0] = fac_1[0] = 1;
    for (int i = 1; i < maxn; i++)
        fac[i] = fac[i - 1] * i%mod,
        fac_1[i] = fac_1[i - 1] * inv[i] % mod;
}
LL C(int n, int m)
{
    if (n < m || n < 0 || m < 0)return 0;
    return fac[n] * fac_1[n - m] % mod*fac_1[m] % mod;
}

#define N 101
struct matrix {
    int m[N][N];
};
matrix b, ans;
char str[101];
int len;
void init1()
{
    int i;
    memset(b.m, 0, sizeof(b.m));
    for (i = 1; i < len; i++)
        b.m[i][i] = b.m[i][i - 1] = 1;
    b.m[0][0] = b.m[0][len - 1] = 1;//第一个字符与最后一个结合 

}
matrix mul(matrix a, matrix b)
{
    int i, j, k;
    matrix c;
    for (i = 0; i < len; i++)
        for (j = 0; j < len; j++)
        {
            c.m[i][j] = 0;
            for (k = 0; k < len; k++)
                c.m[i][j] += (a.m[i][k] * b.m[k][j]);
        }
    return c;
}
void mpow(matrix ma, int n)
{
    int i;
    memset(ans.m, 0, sizeof(ans.m));
    for (i = 0; i < len; i++)
        ans.m[i][i] = 1;
    for (; n; n >>= 1)
    {
        if (n & 1)
            ans = mul(ans, ma);
        ma = mul(ma, ma);
    }
}

signed main()
{
    ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
    //getInv();
    //init();

    int t, n, k, m;
    cin >> t;
    while (t--)
    {
        cin >> n >> m;
        int tmp = abs(n - m);
        int Min = max(n, m);
        int ans1 = inf, ans2 = 0;
        
        int sq = sqrt(tmp);
        for (int i = 1; i <= Min && i <= sq; i++)
        {
            if (tmp%i == 0)
            {
                if(i>1)
                    ans1 = min(ans1, i),
                    ans2 = max(ans2, i);
                if (tmp / i <= Min&&tmp/i>1)
                    ans1 = min(ans1, tmp / i),
                    ans2 = max(ans2, tmp / i);
            }
        }
        if (n == m)
        {
            if(n>1)
            cout << 2 << ' ' << n << '\n';
            else cout << "-1 -1\n";
        }
        else
        if (ans1 == inf)
            cout << "-1 -1\n";
        else cout << ans1 << ' ' << ans2 << '\n';
    }
    //system("pause");
    return 0;
}