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: I want to hear your thoughts... how do you feel about the President's decision to replace Gen. McChrystal with Gen. Petraeus?  Responser: It's the right choice in a tough situation. It has the (almost certainly unintended) benefit of making it much more difficult to pull out of Afghanistan before the job is done.
