Some stations that broadcast from smaller cities are private affiliates of the CBC, that is, stations which are owned by commercial broadcasters but predominantly incorporate CBC programming within their schedules. Such stations generally follow the CBC schedule, airing a minimum 40 hours per week of network programming. However, they may opt out of some CBC programming in order to air locally produced programs, syndicated series or programs purchased from other broadcasters, such as CTV Two, which do not have a broadcast outlet in the same market. In these cases, the CBC programming being displaced may be broadcast at a different time than the network, or may not be broadcast on the station at all. Most private affiliates generally opt out of CBC's afternoon schedule and Thursday night arts programming. Private affiliates carry the 10 p.m. broadcast of The National as a core part of the CBC schedule, but generally omitted the 11 p.m. repeat (which is no longer broadcast). Most private affiliates produce their own local newscasts for a duration of at least 35 minutes. Some of the private affiliates have begun adding CBC's overnight programming to their schedules since the network began broadcasting 24 hours a day.
CBC's contract states all affiliates must broadcast how many hours a day?