CF1389A.LCM Problem

Let $LCM(x, y)$ be the minimum positive integer that is divisible by both $x$ and $y$ . For example, $LCM(13, 37) = 481$ , $LCM(9, 6) = 18$ .

You are given two integers $l$ and $r$ . Find two integers $x$ and $y$ such that $l \le x < y \le r$ and $l \le LCM(x, y) \le r$ .

The first line contains one integer $t$ ( $1 \le t \le 10000$ ) — the number of test cases.

Each test case is represented by one line containing two integers $l$ and $r$ ( $1 \le l < r \le 10^9$ ).

For each test case, print two integers:

• if it is impossible to find integers $x$ and $y$ meeting the constraints in the statement, print two integers equal to $-1$ ;
• otherwise, print the values of $x$ and $y$ (if there are multiple valid answers, you may print any of them).