Instruct: Classify an Amazon review as either positive or negative.
Query: The reason this exists.

Aerosmith is contractually obligated to Sony Music to deliver another record this year. They had begun recording one, but Steven Tyler had to have throat surgery - taking him away from singing for months - and another bandmember was diagnosed with cancer and has begun treatment, preventing him from playing with the band also.In order to fulfill their contract they put out a Greatest Hits, and because it contains two new songs (one an old demo from the Pump days, actually) it is technically a "new album."So there you go.