You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named (9R,10R,13R,14R)-14-[(E,5S)-5,6-dimethylhept-3-en-2-yl]-9,13-dimethyltetracyclo[8.7.0.01,13.04,9]heptadec-4-ene-3,6,17-trione by IUPAC nomenclature, provide its molecular formula.
user
C28H40O3
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