You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
[(2S)-1-(2-bromo-4-methylanilino)-1-oxopropan-2-yl] 5,6-dihydro-4H-cyclopenta[b]thiophene-2-carboxylate is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H18BrNO3S
assistant