19480
Graphitic carbon nitride nanosheets are extracted , produced via simple liquid - phase exfoliation of a layered bulk material , g - C3 N4 .
 Chemical: Graphitic carbon nitride; Chemical: C3 N4
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: Graphitic carbon nitride, C3 N4 
Answer:
 Chemical: Graphitic carbon nitride; Chemical: C3 N4