Given reviews from Amazon, classify those review based on their content into two classes: Negative or Positive.
Example: I've read this book with much expectation, it was very boring all through out the book
Example solution: Negative
Example explanation: Review writer does not like the book because it was boring, therefore it is a negative review.

Problem: I purchased this adapter to replace another PS-AC4 that worked for about 18 months before going belly up. This one lasted two weeks. I called MacAlly and quickly got an RMA number, then I overnighted the defective item to them. That was ten days ago, and I'm still waiting for the replacement to arrive.
Solution: Negative