You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(8S,9S,10R,13S,14S,17R)-17-[(2S)-3-ethyl-6-methylhept-3-en-2-yl]-10,13-dimethyl-1,2,6,7,8,9,11,12,14,15,16,17-dodecahydrocyclopenta[a]phenanthren-3-one is the IUPAC name of a molecule. Please give its molecular formula.
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