You are given positive integers $N$ and $M$. Find the smallest positive integer $X$ that satisfies both of the conditions below, or print $-1$ if there is no such integer. - $X$ can be represented as the product of two integers $a$ and $b$ between $1$ and $N$, inclusive. Here, $a$ and $b$ may be the same. - $X$ is at least $M$. ### Constraints - $1\leq N\leq 10^{12}$ - $1\leq M\leq 10^{12}$ - $N$ and $M$ are integers.

The input is given from Standard Input in the following format: $N$ $M$

Print the smallest positive integer $X$ that satisfies both of the conditions, or $-1$ if there is no such integer.