Given the task definition, example input & output, solve the new input case.
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
Output: Negative
Review writer does not like the book because it was boring, therefore it is a negative review.

New input case for you: Gifford is one of the top experts on Heinlein's works, and his "A Reader's Companion" is an exhaustively researched and well-thought-out compendium of nearly all of Heinlein's work.I say "nearly" only because the book misses a few Heinlein collections and such that have been published in the few years since Gifford's 2000 printing. [...]I've been collecting Heinlein works for years, even very obscure ones, and I still learned of new things from Gifford's book.
Output:
Positive