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: Climate change is one of the greatest challenges facing our planet, and we have been dragging our feet to find a solution. This is not a problem to be solved by our children and grandchildren. Action cannot wait any longer. #ActOnClimate  Responser: You can't deny what doesn't exist.
