In this task, you're given a review from Amazon. Your task is to generate a rating for the product on a scale of 1-5 based on the review. The rating means 1: extremely poor, 2: poor, 3: neutral, 4: good, 5: extremely good.

I purchased this diffuser for my classroom to provide aromatherapy to students. After about six months of daily use, it had become so dirty and sticky that I threw it away. I tried cleaning it without lasting results. I will note, that despite having aesthetic issues, the diffuser was still functional and working at the time of disposal. If I were looking for a higher quality and/or aesthetically pleasing diffuser, I would purchase a different product.

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
3