You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
What is the molecular formula of the molecule identified by (3aS,7S,8aS)-7-methyl-3-methylidene-6-[(E)-3-oxobut-1-enyl]-4,7,8,8a-tetrahydro-3aH-cyclohepta[b]furan-2-one ?
user
C15H18O3
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