You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
[(1R,3S,4R,8R,9Z)-10-(hydroxymethyl)-1-methyl-5-methylidene-6,13-dioxo-14-oxatricyclo[9.2.1.04,8]tetradeca-9,11-dien-3-yl] 2-methylprop-2-enoate is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H22O6
assistant