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

Now, solve this: Works great and compact and convenient. The detachable lanyard is nice for when I don't want to carry my pack with me. I don't see myself using the white and black cards too often, but they're nice to have. The cards are of a nice quality, thick enough to not bend accidentally when in the camera bag.
Solution:
Positive