4840
Approximately 1.5 " million years ago , the Missouri River flowed northward into a terminal lake .
 location: Missouri River
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: Missouri River 
Answer:
 location: Missouri River