You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named [(4R,4'aS,5R,8'aS,10'aR)-1',1',4,4'a,5-pentamethylspiro[1,3-dioxolane-2,2'-3,4,6,7,8,9,10,10a-octahydrophenanthrene]-8'a-yl]methanol by IUPAC nomenclature, provide its molecular formula.
user
C22H36O3
assistant