1480
The eighth anniversary special of " Late Night with David Letterman " , airing in 1990 , began with a scene at Cheers , in which the bar 's TV gets stuck on NBC , and all of the bar patrons decide to go home instead of staying to watch David Letterman .
 organization: NBC; person: David Letterman
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
 Entities: NBC, David Letterman 
Answer:
 organization: NBC; person: David Letterman