You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Can you give the molecular formula of the molecule 4-[(4aS,10bS)-8,9-dimethoxy-1,2,3,4,4a,10b-hexahydrophenanthridin-6-yl]benzenesulfonamide ?
user
C21H24N2O4S
assistant