You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2,4,8-trimethyl-3-[(9-methyl-11-oxabicyclo[4.4.1]undec-2-en-3-yl)methyl]spiro[5.5]undec-3-en-11-ol is the IUPAC name of a molecule. Please give its molecular formula.
user
C26H42O2
assistant