You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule (2aR,5'S,5aS,6R,7R,9R,9aR)-5'-(furan-3-yl)-9-hydroxy-2a-(hydroxymethyl)-7-methylspiro[1,3,4,5,5a,7,8,9-octahydronaphtho[1,8a-b]oxete-6,3'-oxolane]-2'-one .
user
C20H26O6
assistant