You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named methyl 4-bromo-3-(2-ethoxy-2-oxoethoxy)-5-[3-(ethylsulfonylamino)phenyl]thiophene-2-carboxylate by IUPAC nomenclature, provide its molecular formula.
user
C18H20BrNO7S2
assistant