5554
These communication nets were termed " keys " at Bletchley Park , and were assigned code names , such as " Red " , " Chaffinch " , and " Shark " .
 Bletchley Park, Chaffinch, Shark
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Bletchley Park, Chaffinch, Shark