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He hosted late night television talk shows for 33 years , beginning with the February 1 , 1982 , debut of " Late Night with David Letterman " on NBC , and ending with the May 20 , 2015 , broadcast of " Late Show with David Letterman " on CBS .
 organization: NBC; organization: CBS
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 organization: NBC; organization: CBS