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

[EX Q]: This DVD is one of my all time favorite musical DVDs. Miss Jackson proves why she is the highest paid singer in the industry. With a combination of costume changes, great choreography, Janet's greatest hits, and a sold out crowd at Madison Square Garden, the DVD makes for an excellent night of entertainment. I only regret that I was not able to see the concert in person here in my home town due to a cancelation of the concert;however, the DVD is definately a suitable substitute. I highly recommend this DVD to any fans of Janet, lovers of music, and owners of quality DVDs.
[EX A]: Positive

[EX Q]: I bought this air mattress to use while my new bed was being shipped from back east, the bed lost air every night and I woke up almost on the floor. I tried to send it back but it was impossible to get back into the box.
[EX A]: Negative

[EX Q]: The book has great instruction and drills. It is good for those who have a solid foundation with joint locks and submissions and an overall solid grasp of the body and movement. It has given some good variations of techniques I already teach and use.
[EX A]:
Positive