for i in range(int(input())):
x, y = map(int, input().split())
if (x+y) % 2==1:
print('-1 -1')
elif x%2==1:
if x > y:
print(int((x+y)/2)-y,y)
else:
print(x,int((x+y)/2)-x)
else:
print(int(x/2),int(y/2))#include<bits/stdc++.h>
using namespace std;
#define ff first
#define ss second
#define ll long long
int main(){
int t;
cin>>t;
while(t--){
int a,b;
cin>>a>>b;
if((a+b)&1){
cout<<"-1 -1"<<endl;
}
else{
if(a&1){
if(a>b){
cout<<(a-b)/2<<" "<<b<<endl;
}
else{
cout<<a<<" "<<(b-a)/2<<endl;
}
}
else{
cout<<a/2<<" "<<b/2<<endl;
}
}
}
}
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