Given reviews from Amazon, classify those review based on their content into two classes: Negative or Positive.

Example Input: Book is over 600 pages and the print is so small it was difficult for me to try to read so I returned it. Perhaps if it ever comes out on Kindle I would try again.
Example Output: Negative

Example Input: not bad but be warned you need to buy extra play-doh at local store before handing it to the kid's
Example Output: Positive

Example Input: I was looking for a shower door that could open from either the left or the right and I did not want one to choose for me. This door ticks and fits all the right boxes in that department. I like the crystal glass effect too. It is very clear and allows a lot of light into the shower hub. It is frameless too which is what was asked for by the wife.Its sturdy quarter of an inch thick glass also is a nice feature. But most of all the pivot door is a feature I got on with too.
Example Output:
Positive