You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 1-[(3S,8S,9S,10S,11R,13S,14S,17S)-3,11-dihydroxy-10,13-dimethyl-2,3,4,5,6,7,8,9,11,12,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-17-yl]-2-hydroxyethanone by IUPAC nomenclature, provide its molecular formula.
user
C21H34O4
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