You can calculate rapidly up to 13 anyway.

Desk Set is a 1957 American romantic comedy film directed by Walter Lang and starring Spencer Tracy and Katharine Hepburn. The screenplay was written by Phoebe Ephron and Henry Ephrons from the 1955 play of the same name by William Marchant. The film was released as His Other Woman in the UK. See also: Resolute desk, Western Electric hand telephone sets, Help desk, Telephone, Sue Randall, and Partners desk.