You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 2-[1-(thiophene-2-carbonyl)piperidine-4-carbonyl]-3,4-dihydro-1H-isoquinoline-3-carboxamide by IUPAC nomenclature, provide its molecular formula.
user
C21H23N3O3S
assistant