You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(4aS,9Z,12aR)-2,3,4,4a,6,7,8,11,12,12a-decahydropyrano[3,2-b]oxecine The above is the IUPAC name of a molecule. Write its molecular formula.
user
C12H20O2
assistant