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: Merry Christmas! Keep our troops & their families serving overseas in your thoughts & prayers this holiday season.  Responser: Merry Christmas & Happy New Year!
