You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
What is the molecular formula of the molecule identified by (3aR,4R,5S,5aS,6S,8R,8aS,9R,9aS)-4,6,8,9-tetrahydroxy-5,8a-dimethyl-1-methylidene-4,5,5a,6,7,8,9,9a-octahydro-3aH-azuleno[6,5-b]furan-2-one ?
user
C15H22O6
assistant