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: Happy Birthday Congressman Dave Reichert! My #WA district neighbor & a partner in helping expand the Alpine Lakes wilderness.  Responser: There is nothing on his timeline to indicate it's his birthday..Happy birthday anyway.
