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: At a "meet & greet" hosted by supporters in Elk Grove Village:  Responser: Happy Birthday Tammy! Thank you for meeting with us in Elk Grove.
