You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named (3aR,5Z,9E,11aS)-6-(hydroxymethyl)-10-methyl-3-methylidene-3a,4,7,8,11,11a-hexahydrocyclodeca[b]furan-2-one by IUPAC nomenclature, provide its molecular formula.
user
C15H20O3
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