You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named ethyl 7-[4-[4-(1-benzothiophen-4-yl)piperazin-1-yl]butoxy]-2-oxoquinoline-1-carboxylate by IUPAC nomenclature, provide its molecular formula.
user
C28H31N3O4S
assistant