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Despite its official name , the ( Deutsche U-Halbflotille Pola : German U-Boat Half-Flotilla , Pola ) , it operated mainly from an advanced base at Cattaro , at the entrance to the Adriatic .
 Pola, Pola, Cattaro
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Pola, Pola, Cattaro