You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
4-[[(1S,9S,12S)-3-chloro-6-hydroxy-1-methyl-8-oxo-11-oxatricyclo[7.2.1.02,7]dodeca-2,4,6-trien-12-yl]methyl]-2,5-dihydroxy-3,6-dioxocyclohexa-1,4-diene-1-carboxamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H16ClNO8
assistant