A13588 | $LCM Problem$

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内存限制256MB

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题目描述

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).

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