## Geometric Sequence

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

The number of integers, 2 ≤ N ≤ 100,000N lines, each with one non-zero integer x ( |x| ≤ 10^18 )

### Output

The ratio of the original sequence (if one exists).The relative error of the answer must be within 10^-9. ( |answer - expected| / |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.

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Best Solutions

**Point Value:** 10

**Time Limit:** 1.00s

**Memory Limit:** 64M

**Added:** Sep 26, 2008

**Author:** hansonw1

**Problem Types:**[Show]

**Languages Allowed:**

C++03, PAS, C, HASK, ASM, RUBY, PYTH2, JAVA, PHP, SCM, CAML, PERL, C#, C++11, PYTH3

## Comments (Search)

javicon Feb 06, 2009 - 3:16:12 am UTC = =that makes my algorithm totally fail = =

gonna take a break XD

zhxl0903on Feb 01, 2009 - 6:21:55 pm UTC can there be decimal ratios?bbi5291on Feb 01, 2009 - 6:26:29 pm UTC Re: can there be decimal ratios?Note:

If the answer were guaranteed to be an integer, this line would be unnecessary, since integers are exact numbers. These lines are only included when the answer can be a floating-point number, because then your answer might be off by a tiny bit depending on how you obtained it - meaning it will still be judged correct if you have an error of less than one part in a billion (thousand million?)

hansonw1on Nov 29, 2008 - 3:30:37 am UTC Hint 3hansonw1on Oct 21, 2008 - 1:25:08 pm UTC Hint 2hansonw1on Oct 21, 2008 - 1:24:45 pm UTC Hint 1