20070
Eighty female Sprague - Dawley ( SD ) rats were divided randomly into four groups of 20 : one control group and three NaF treated groups .
 Chemical: NaF
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: NaF 
Answer:
 Chemical: NaF