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

Example Input: I was very excited to buy this scanner and was pleased with its size and weight. However, if you have a Vista operating system, like I do, IT WILL NOT WORK! The company told me that they stopped selling this product over a year ago and there are no driver updates available for this product. If you have an older computer and an older operating system this product might work for you. But as for me it was a waste of money!
Example Output: Negative

Example Input: Had no luck, even with latest firmware, getting the unit to resume any of my audio books. I tried changing the tags on the mp3 files but it did not work. The unit would go into auto shut off and then force you to start your audio book file from the start every time.
Example Output: Negative

Example Input: I needed to upgrade from 128 MB to 512 MB. The memory got to my home through UPS (plus a dog bone for my dog) within about 5 days. Installed easily once I figured out where HP had the memory on the motherboard (behind the drive chassis!). Everything is working like a champ. Excellent buy and compatibility for an upgrade.
Example Output:
Positive