You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named (2R,3R,4R,4aR,9aS,10R)-2,3,4,8,10-pentahydroxy-6-methoxy-3-methyl-1,2,4,4a,9a,10-hexahydroanthracen-9-one by IUPAC nomenclature, provide its molecular formula.
user
C16H20O7
assistant