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: Into the quarterfinals!! Beat Aiko Nakamura, a former top 50 player, 7-5, 6-3 today. I will play Johanna Konta tomorrow afternoon! :)  Responser: I have a signed Teddy bear that I got from Aiko Nakamura in Japan during the Japan Open! Haha
