22695
They include : A UFO attack , two nuclear meltdown scenarios , two major chemical spill scenarios , a large flood , a major hurricane , two firestorm scenarios , a volcano , an earthquake , a high power microwave beam misfire , riots , and a typhoon .
 None
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:  
Answer:
 None