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

Example Input: I haven't been able to watch this much because the DVD won't play in my normal (otherwise functioning) DVD player. It will play on my computer's DVD player, but without sound. The DVD will play fine on my laptop, but that's not a screen that's very conducive to practicing in front of. The DVD does play on my friend's DVD player for some reason. Also, I bought volumes 1 and 2 and both are so short, it seems obvious that they could have put all of the lessons on one DVD. I guess they knew they could make more money by making us buy both.
Example Output: Negative

Example Input: Great book for people that need to write email. It would be nice to review the grammar rule's from time to time.
Example Output: Positive

Example Input: I think the concept is great but with this particular product, they have these sections that are thicker rubber (or whatever the material is) and it literally pushed into my ribs every time I sit down. I commute a lot and have a desk job so its not a very pleasant experience to have that pushing and bruising your rubs every day. It would've been nice except for those thicker lines of rubber that aren't very flexible.
Example Output:
Negative