21501
Previously , we have confirmed that the antiviral activities of the chromone derivatives were controlled by the type as well as the position of the substituents attached to the chromone core structure .
 Chemical: chromone; Chemical: chromone
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: chromone; Chemical: chromone