You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(8E)-5,5,7,7-tetramethyl-8-(4-methylpent-4-en-2-ylidene)-2,3,4,5a,6,9,10,10a-octahydro-1H-heptalene The above is the IUPAC name of a molecule. Write its molecular formula.
user
C22H38
assistant