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: This work is an exhaustive study of the Luftwaffe's inventory from 1931 - 1945. Naturally the famous are here: Ju87, Me109/110/262, Fw190, He111/162, but the obscure as well: the Bv40 Interceptor Glider(!), the asymmetric Bv141 observation aircraft, and the He100 fighter. The entries (with drawings or photographs) of these one-off variants and technological near-misses make the volume worth owning. Over 150 fixed-wing aircraft, gliders and helicopters are combined with an excellent overview of the Luftwaffe from creation to destruction. Additionally, appendices contain the Luftwaffe's chain of command, and a glossary of Luftwaffe-speak.If you are a student of WW2, and particularly the airwar, then you should definitely try to pick up a copy. Highly recommended.
Solution:
Positive