Silly Slp knows nothing about number theory. One day he feels puzzled with the following problem.
Give two positive integers $n$ and $c$. Find a pair of positive integer ($a, b$), which satisfies both of $a$ and $b$ are no more than $n$ and the lowest common multiple of them is $c$. Moreover, maximize $a \times b$, the product of $a$ and $b$.
Please tell Silly Slp the maximize value of $a \times b$. If $a$ and $b$ don't exist, print “-$1$”(without quotes).
