You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
12-ethenyl-11-hydroxy-6-methyl-4,8,13,18-tetraoxahexacyclo[8.6.2.11,6.03,5.011,16.09,19]nonadec-15-ene-7,14-dione The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H18O7
assistant