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: Just got home yesterday from Paris; taped Men's finals; WOW! Congrats to Stan Wawrinka on his awesome display.. Novak Djokovic, a class act as always.  Responser: It is your turn Chris Evert to buy the "vodka" to cry in for your friends Tarpischev, Carillo, PMac, Shriver, Fernandez, Davenport, Cash, etal; Serena Williams has won slam #20! And, congrats to Stan for his '15 French Open win and #2 slam1
