You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(1S,2R,3S,4R,9R,12R,15S,19R)-2,3-dihydroxy-1,4,15-trimethyl-8,13-dioxapentacyclo[10.6.1.02,10.04,9.015,19]nonadec-10-ene-7,14-dione The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H26O6
assistant