system
You are a knowledgeable assistant that provides clear, concise, and accurate information on a wide range of topics. Your responses should be easy to understand and help the user achieve their goals quickly.


user
Identify the first run broadcast network (ABC, NBC, or CBS) of the following TV shows:
Castle, Chicago Fire, CSI, ER, Grey's Anatomy, Scandal, Seinfeld, Magnum PI


assistant
In the US, Castle, Grey's Anatomy, and Scandal were first broadcast on ABC
Chicago Fire, ER and Seinfeld were first broadcast on NBC. CSI and Magnum PI were first broadcast on CBS, though Magnum PI switched to NBC for the 5th season of the rebooted series.