You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
3-(4-tert-butylphenyl)-5-[(2,6-difluorophenyl)methylsulfanyl]-4-ethyl-1,2,4-triazole is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H23F2N3S
assistant