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 (4aR,5aS,8aS,13aS,15aS,15bR)-2,4a,5,5a,6,7,8,13a,15,15a,15b,16-dodecahydro4,6-methanoindolo[3,2,1-ij]oxepino[2,3,4-de]pyrrolo[2,3-h]quinolin-6-ium-14-one;hydrogen sulfate;dihydrate .
user
C21H28N2O8S
assistant