You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 4-O-ethyl 2-O-methyl 5-[(3-chloro-7-nitro-1-benzothiophene-2-carbonyl)amino]-3-methylthiophene-2,4-dicarboxylate by IUPAC nomenclature, provide its molecular formula.
user
C19H15ClN2O7S2
assistant