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: Nice in theory, but doesn't really do the trick. We thought the longer shaft and small profile would make it easy to hold it in the right spot during intercourse to give me the extra zing necessary. The problem is, the surface is difficult to press up against the right spot. If the paddle had a nub on it or it was convex would make it a lot better.I was also disappointed in the speed/strength. In order to turn it on, you have to twist the base. The problem is, it goes from zero to full strength. No gradual increase. The strength is a little much to start off, and usually not enough after a short while. It would be nice if the power were adjustable.Positive: Very easy to clean - waterproof - inexpensive - slender design makes it easy to bring with you anywhere.
Solution:
Negative