You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule 4-[(4aR,8aR)-3,4,4a,5,6,7,8,8a-octahydro-1H-isoquinoline-2-carbonyl]-N-ethylbenzenesulfonamide .
user
C18H26N2O3S
assistant