You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance 3-methyl-5-(6-methylhept-5-en-2-yl)spiro[3a,4,5,6,7,8a-hexahydro-1H-azulene-8,2'-oxirane]-4-ol .
user
C20H32O2
assistant