Task: Calculate the intensity of emotion E in the tweet as a decimal value ranging from 0 to 1, with 0 representing the lowest intensity and 1 representing the highest intensity.
Tweet: Thank you @Pret 4 giving me a free coffee for bringing my reusable cup to the airport because it was 1st time you saw one. But #depressing
Emotion: sadness
Intensity score: 
0.625