You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance N-[4-[(3E)-3-[(3,4-dihydroxy-5-methoxyphenyl)methylidene]-2,5-dioxopyrrolidin-1-yl]phenyl]acetamide .
user
C20H18N2O6
assistant