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: The Dirty Air Act goes down. This is a victory for clean air, clean energy job growth and sound science.  Responser: Thanks for all your hard work Senator Merkley! I hear so many good things about our 'Freshman Senator'!!!
