#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define mem(x) memset(x,0,sizeof(x))
#define printYes puts("Yes")
#define printYES puts("YES")
#define printNo puts("No")
#define printNO puts("NO")

const ll inf=1000000000000000000; 
const ll mod=998244353;

int n,m,T; 

inline int read()
{
    int F=1,ANS=0;
    char C=getchar();
    while (C<'0'||C>'9')
    {
        if (C=='-') F=-1;
        C=getchar();
    }
    while (C>='0'&&C<='9')
    {
        ANS=ANS*10+C-'0';
        C=getchar();
    }
    return F*ANS;
}
inline char readchar()
{
    char C=getchar();
    while (C<33||C>126) C=getchar();
    return C;
}
inline int raed(){return read();}
void work()
{
    ll x,y,ansx,ansy;
    cin >> x >> y;
    ansy=abs(x-y);
    if (ansy==0) 
    {
        if (x==1) printf("-1 -1\n");
        else printf("2 %lld\n",x);
        return;
    }
    if (ansy==1) printf("-1 -1\n");
    else 
    {
        ansx=ansy;
        for (ll i=2;i<=sqrt(ansy);i++)
        {
            if (ansy%i==0) 
            {
                ansx=i;
                break;
            }
        }
        printf("%lld %lld\n",ansx,ansy);
    }
    return;
}

int main()
{
    int tp=0;
    //0 : many test cases
    //1 : one test case
    if (tp==0) T=read();
    else T=1;
    while (T--)
    {
        work();
    }
    return 0;
}