8622
Importantly , there have been notable incidents , including accidental deaths , due to falls from steep cliffs ( a misstep could be fatal in this class 4 / 5 terrain ) and due to falling rocks , over the years , including 1993 , 2007 ( involving an experienced NOLS leader ) , 2015 and 2018 .
 organization: NOLS
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
 Entities: NOLS 
Answer:
 organization: NOLS