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: As a stockholder, I am joining the International Union of Machinists in calling on Caterpillar to negotiate in good faith.  Responser: The public sector union was so awesome in wisconsin that it lost 60% of it's members when they were no longer forced to pay dues.
