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The vessel patrolled the waters of the 2nd Naval District to prevent incursions by German U-boats and to locate any mines laid by either U-boats or surface raiders .
 organization: 2nd Naval District; location: German
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: 2nd Naval District; location: German