N Is a Number: A Portrait of Paul Erdős is a 1993 documentary directed by George Paul Csicsery about the life of mathematician Paul Erdős. 　　Erdős himself appears in the film. As of 2007, using the official cast list in the credits, it gives Erdős a Bacon number (and thus Erdős-Bacon number) of 4. However, Sir Alec Guinness, identified by name by the narrator, appears in the film, getting an honorary doctorate with Erdős; his presence would give Erdős a Bacon number of 3. Since Frost/Nixon was released in late 2008, Erdős has a Bacon number of 3 through official credits.