You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(2R,4aS,8aS)-2-methyl-4a,5,6,7,8,8a-hexahydro-4H-benzo[d][1,3]dithiine The above is the IUPAC name of a molecule. Write its molecular formula.
user
C9H16S2
assistant