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The show had previously used pre-credits teaser sequences , but only for some special episodes in the 1980 s , such as the post-regeneration " Castrovalva " ( 1982 ) ; the 20th - anniversary special , " The Five Doctors " ( 1983 ) ; and the 25th - anniversary story , " Remembrance of the Daleks " ( 1988 ) .
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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:
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