Task: Categorize the tweet into an intensity level of the specified emotion E, representing the mental state of the tweeter. 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: Regret for the things we did can be tempered by time; it is regret for the things we did not do that is inconsolable. - Sydney J. Harris
Emotion: sadness
Intensity class: 
0: no sadness can be inferred