Instruct: Classify an Amazon review as either positive or negative.
Query: not worth the money

It maybe only takes 2 hours but after 1/2 way through the second 20 min treatment I was asking myself "what the heck was I thinking". I couldn't really get the trays to fit well and stay in my mouth, very slimy, just awful. Not worth the money. There has got to be a better way to do this.