You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance N-[1-(2-ethenylphenyl)ethenyl]-3,4,4-trifluoro-2-(2-fluorophenyl)sulfanyl-N-methylbut-3-en-1-amine .
user
C21H19F4NS
assistant