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: Exciting news! Alaska Airlines' new non-stop flight between Portland and DC will be great for businesses, tourism, and our overall economy.  Responser: Now THAT is a flight I will book routinely. Right on!
