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What is the molecular formula of the compound with this IUPAC name 8,10,13-trimethyl-17-(4-methylidenecyclohexa-1,5-dien-1-yl)-1,2,3,4,5,6,7,9,11,12,14,15,16,17-tetradecahydrocyclopenta[a]phenanthrene ?
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C27H40
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