You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Name the molecular formula for the molecule established as 4a-methyl-8-methylidene-2-propan-2-yl-3,4,5,6,7,8a-hexahydro-2H-naphthalen-1-one using the IUPAC nomenclature.
user
C15H24O
assistant