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 100\,000~.
~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.