You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(2S)-2-(5-chloro-2-methyl-N-methylsulfonylanilino)-N-[(1S)-1-(3,4-dimethoxyphenyl)ethyl]propanamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H27ClN2O5S
assistant