You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(1S,2R,4S,5R,6R,9S,10S,17R)-5,10,15-trihydroxy-12-(1-hydroxyethyl)-1,6-dimethyl-3,8,13-trioxapentacyclo[7.7.1.02,4.06,17.011,16]heptadec-11(16)-ene-7,14-dione The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H22O9
assistant