A sequence of integers is called a geometric sequence if the ratio of consecutive numbers is constant.
For example, $(3,6,12,24)$ is a geometric sequence (each term is equal to twice the previous number).

Now, with such a sequence, we will shuffle it around and remove some of the elements.
Given the result of such a transformation, try to recover the "geometric ratio" of the original sequence.

If there are multiple values, output the one with the greatest absolute value (if there's still a tie, output the positive one).
If there is no such sequence, output 0.

Input Specification

The number of integers, $2\le N\le 100000$.
$N$ lines, each with one non-zero integer $x$ $(|x|\le {10}^{18})$.

Output Specification

The ratio of the original sequence (if one exists).
The relative error of the answer must be within ${10}^{-9}$.

$${\displaystyle \frac{|\text{answer}-\text{expected}|}{|\text{expected}|}<{10}^{-9}}$$

Sample Input

3
1
3
27

Sample Output

3

The original sequence could have been $1,3,9,27$ or $27,9,3,1$; the former has the greater ratio.