Task: Determine the appropriate intensity class for the tweet, reflecting the level of emotion E experienced by the user. 0: no E can be inferred. 1: low amount of E can be inferred. 2: moderate amount of E can be inferred. 3: high amount of E can be inferred.
Tweet: Happy Birthday Roy Buchanan, born on this day in 1939. #roybuchanan #guitar #blues #happybrithday
Emotion: sadness
Intensity class: 
0: no sadness can be inferred