Definition: Given a 'poster' sentence and a corresponding 'response' (often, from Facebook or Reddit)classify the sentiment of the given response into four categories: 1) Positive, 2) Negative, 3) Neutral, and 4) Mixed if it contains both positive and negative.
Input: Poster: This year we're giving gifts that never stop sucking -- metal straws. To get yours, take the "Refuse" Plastic Pledge and join the Plastic Pollution Coalition: http://plasticpollutioncoalition.org/support/join/  Responser: Will share this site!
