You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
3-[2-(1-hydroxy-2,5,5,8a-tetramethyl-3,4,4a,6,7,8-hexahydro-2H-naphthalen-1-yl)ethyl]-2H-furan-5-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H32O3
assistant