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: http://m.wtatennis.com/default.aspx?s=news-display&aid=4775439  Responser: Congrats Beth. Great effort
