You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named (5S,8S,9S,10S,11R,13S,14S,17R)-10,13,17-trimethyl-1,2,3,4,5,6,7,8,9,11,12,14,15,16-tetradecahydrocyclopenta[a]phenanthrene-11,17-diol by IUPAC nomenclature, provide its molecular formula.
user
C20H34O2
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