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 Saturday, Elizabeth will be in Halifax talking climate change. Hope to see you there! https://www.facebook.com/events/673195326125691/  Responser: Elizabeth May, you are a wonder.
