You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named (8S,9R,10R,13R,14S,16R,17R)-17-[(E)-2,6-dihydroxy-6-methyl-3-oxohept-4-en-2-yl]-2,16-dihydroxy-4,4,9,13,14-pentamethyl-8,10,12,15,16,17-hexahydro-7H-cyclopenta[a]phenanthrene-3,11-dione by IUPAC nomenclature, provide its molecular formula.
user
C30H42O7
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