Task: Question Answering
Input (English): Passage: The film opens with a montage of images of Manhattan and other parts of New York City accompanied by George Gershwin's Rhapsody in Blue, with Isaac Davis narrating drafts of an introduction to a book about a man who loves the city. Isaac is a twice-divorced, 42-year-old television comedy writer who quits his unfulfilling job. He is dating Tracy, a 17-year-old girl attending the Dalton School. His best friend, college professor Yale Pollack, married to Emily, is having an affair with Mary Wilkie. Mary's ex-husband and former teacher, Jeremiah, also appears, and Isaac's ex-wife Jill Davis is writing a confessional book about their marriage. Jill has also since come out as a lesbian and lives with her partner, Connie.
When Isaac meets Mary, her cultural snobbery rubs him the wrong way. Isaac runs into her again at an Equal Rights Amendment fund-raising event at the Museum of Modern Art hosted by Bella Abzug (playing herself) and accompanies her on a cab ride home. They chat until sunrise in a sequence that culminates in the iconic shot of the Queensboro Bridge. In spite of a growing attraction to Mary, Isaac continues his relationship with Tracy but emphasizes that theirs cannot be a serious relationship and encourages her to go to London to study acting. In another iconic scene, at Tracy's request, they go on a carriage ride through Central Park. 
Question: What is the last name of the person who quits his job?
Output (English): Davis.