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: If you've already signed Sean's birthday card here: http://duffyforcongress.com/happybirthday, please share this image with your friends and ask them to add their names as well.  Responser: Happy Birthday to Sean Duffy! It's my dad's birthday too #88.
