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 (3R,4S,4aR,5S,8aR)-3-hydroxy-4-(hydroxymethyl)-3,4a,8,8-tetramethyl-5-[(2R,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy-2,4,5,6,7,8a-hexahydronaphthalen-1-one .
user
C21H36O9
assistant