You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Can you give the molecular formula of the molecule ethyl 6-[2-(benzylsulfonylcarbamoyl)azetidin-1-yl]-5-cyano-2-(difluoromethyl)pyridine-3-carboxylate ?
user
C21H20F2N4O5S
assistant