91982
List According to the Mountaineering : The Freedom of the Hills , the ten essentials are : The textbook recommends supplementing the ten essentials with : Not every expedition will require the use of an essential item .
 None
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 None