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: Went down 6-4,6-4: Lucic-Baroni too good tonight! Another incredible experience in Acapulco, will be back better next year! Indian Wells coming up next  Responser: Good luck in Indian Wells Shelby!
