t = int(input())
for i in range(t):
l, r = map(int, input().split())
if l * 2 > r:
print(-1, -1)
else:
print(l, l * 2)#include <bits/stdc++.h>
#define endl "\n";
#define ll long long
using namespace std;
int main()
{
ll t;
cin>>t;
while(t--) {
ll a, b;
cin>>a>>b;
if(b%a==0) {
cout<<a<<" "<<b<<endl
}
else {
if(b/a > 1) {
cout<<a<<" "<<a*2<<endl
}
else {
cout<<"-1 -1\n";
}
}
}
return 0;
}416. Partition Equal Subset Sum | 1446. Consecutive Characters |
1618A - Polycarp and Sums of Subsequences | 1618B - Missing Bigram |
938. Range Sum of BST | 147. Insertion Sort List |
310. Minimum Height Trees | 2110. Number of Smooth Descent Periods of a Stock |
2109. Adding Spaces to a String | 2108. Find First Palindromic String in the Array |
394. Decode String | 902. Numbers At Most N Given Digit Set |
221. Maximal Square | 1200. Minimum Absolute Difference |
1619B - Squares and Cubes | 1619A - Square String |
1629B - GCD Arrays | 1629A - Download More RAM |
1629C - Meximum Array | 1629D - Peculiar Movie Preferences |
1629E - Grid Xor | 1629F1 - Game on Sum (Easy Version) |
2148. Count Elements With Strictly Smaller and Greater Elements | 2149. Rearrange Array Elements by Sign |
2150. Find All Lonely Numbers in the Array | 2151. Maximum Good People Based on Statements |
2144. Minimum Cost of Buying Candies With Discount | Non empty subsets |
1630A - And Matching | 1630B - Range and Partition |