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: Back home training before one last trip of 2015 this gym looks familiar... #motivated #mysecondhome  Responser: Btw, we shook hands at Citi Open when you beat Frenchy
