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

Example Input: If you are not in really good shape this is a great product to get ready for P90X. It does get kind of boring because you are doing the same workouts every other day, but they do work. It is only about 30 mins but it is amazing how well it works.
Example Output: Positive

Example Input: This book has solved the problems we had while trying to manage my son's diabetes.You can find all answers in diabetes management.
Example Output: Positive

Example Input: I have an older Craftsman Garage Door Opener. Had replaced the gears to my garage door opener and it would not work right. Would only move a foot or so and stop. Looked up information about what could possibly be wrong and it suggested that the RPM Sensor Assembly probably needed replaced. Replaced it and it now works like a charm. Was much cheaper then buying a whole new automatic garage door opener.
Example Output:
Positive