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: Won my first round of Wimbledon Qualifying today 6-4, 6-2. Making may way one match at a time.  Responser: Congratulations Vicky! You're doing great. :-)
