6394
Thereafter , he practiced judo for two 2-month periods in 1902 and 1904 , not attaining any rank ; he also continued his habit of skinny-dipping in the Potomac River during the winter .
 location: Potomac River
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
Answer:
 location: Potomac River