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At the peak of occupation , which followed the Battle of the Little Bighorn in 1876 until 1881 , there were just under 100 buildings and approximately 1,000 people occupying the post at any given moment including infantry and cavalry companies bivouacking in tents on the parade ground while being resupplied .
 event: Battle of the Little Bighorn
Given options, please tell me the categories of all the listed entity words.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} 
 Entities: Battle of the Little Bighorn 
Answer:
 event: Battle of the Little Bighorn