You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named (8S,9S,10R,13S,14S,17R)-17-acetyl-1-chloro-2,2-dihydroxy-10,13-dimethyl-6,7,8,9,11,12,14,15,16,17-decahydro-1H-cyclopenta[a]phenanthren-3-one by IUPAC nomenclature, provide its molecular formula.
user
C21H29ClO4
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