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

Ex 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.

Ex Output:
Negative

Ex Input:
I purchased the Intex airbed to replace an Aerobed that our cats "loved" too much during a guest visit. Comfort wise, the Intex wins hands down-supportive yet comfortable as well. Convenience wise, it inflates a little slower than our old Aerobed (albeit, there is more to inflate) yet it takes up less room when rolled and stored in the sack that comes with it. The only reason I didn't give it 5 stars is because it is VERY high, so a restless sleeper can fall off pretty easily.

Ex Output:
Positive

Ex Input:
I received this product in the mail yesterday, Put in the batteries and the rotating beads do not work. Complete waste of money.

Ex Output:
Negative