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.

This stuff works used it for the 1st time this morning and instantly noticed results but by 8pm ish I noticed my gums feel a little swollen,I did brush teeth and gums so neat time I will try and avoid brushing gums but it def whitens teeth!
positive