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

Example Input: This product requires a stereo player in which the balance is turned totally to the left. Most auto systems have that capability. However if you have Dolby or SurroundSound, it can be difficult (and maybe impossible) to play the cassette without hearing two recordings at the same time. Unfortunately neither the packaging nor the website will warn you of the problem. You therefore should think before buying. Once you have opened the packaging you may be unable to return the product.
Example Output: Negative

Example Input: I have a small business and it was important that the envelope feeder work well. From day 1, this has been a nightmare. Components of the printer block the envelopes/labels and they don't feed properly. If you use internet postage, you lose money with the misfed labels/envelopes. I'm very disappointed and am shopping for a new printer now, only a short time after purchasing this one.
Example Output: Negative

Example Input: In this unique conbination of biography, commentary, & devotional, Arthur Pink offers an intimate view of the many sides of David. The shepherd, the soldier, the king and the sinner are revealed in a way that cuts to the heart of life's greatest problems.
Example Output:
Positive