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

Ex Input:
I bought this air mattress to use while my new bed was being shipped from back east, the bed lost air every night and I woke up almost on the floor. I tried to send it back but it was impossible to get back into the box.

Ex Output:
Negative


Ex Input:
Not what I expected, the first Transformers was the best. The special effects was great but acting was not, too bad.

Ex Output:
Negative


Ex Input:
This is a great book so far. I am a little farther than halfway into it and it is great. Although the writing is a little choppy at times, it is definitely worth it.

Ex Output:

Positive