You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[(1S)-1-(4-methoxyphenyl)ethyl]-2-[N-methylsulfonyl-4-(trifluoromethyl)anilino]acetamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H21F3N2O4S
assistant