Given the task definition and input, reply with output. In this task, You are given a review of Amazon's food products. Your task is to divide them into two classes: negative or positive, depending on the content of the review.

Absolutely love this collagen! My knees hurt if i walk very much . I noticed after 2 weeks of taking my knees didnt hurt anymore.I guit taking for a few days and knees were hurting again.
positive