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

Let me give you an example: I've read this book with much expectation, it was very boring all through out the book
The answer to this example can be: Negative
Here is why: Review writer does not like the book because it was boring, therefore it is a negative review.

OK. solve this:
Airbed doesn't keep air overnight. If you try to return it you will be charged a restocking fee to restock an airbed that doesn't work so you will get no refund.....exchange it for another crappy airbed...My recommendation is....don't buy this crappy airbed!!
Answer:
Negative