You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named [(2bR,3S,6R,6aS)-7-[dimethyl(phenyl)-lambda4-sulfanyl]-3-hydroxy-2b,3,6,6a,7,7a-hexahydro-2aH-cyclobuta[a]inden-6-yl] acetate by IUPAC nomenclature, provide its molecular formula.
user
C21H26O3S
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