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: Our hearts and prayers are with the runners, the families and the citizens affected by today's tragedy in Boston.  Responser: Thank You Mia....ALL our prayers are with the runners and families of the Boston Marathon.........<3
