#include<stdio.h>
#include<algorithm>

using namespace std;

int gcd(int a,int b){
    return b ? gcd(b,a%b) : a;
}

int main(){
    int t;
    scanf("%d",&t);
    while(t --){
        int a,b;
        scanf("%d %d",&a,&b);
        /*for(int i=2;i<=max(a,b);i++) {
            if(a % i == b % i) printf("---%d\n",i);
        } */
        int k = abs(a - b);
        if(k == 1 || (a == 1 && b == 1)) printf("-1 -1\n");
        else if(k == 0) printf("2 %d\n",a);
        else if(a % 2 == b % 2) printf("2 %d\n",k);
        else {
            int Min = k,Max = k;
            for(int i=2;i<=k/i;i++) {
                if(k % i == 0) {
                    Min = i;
                    break;
                }
            }
            printf("%d %d\n",Min,Max);
        }
    }
    return 0;
}