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 (5S)-4-[hydroxy-(4-methylphenyl)methylidene]-1-[(2R)-2-hydroxypropyl]-5-pyridin-3-ylpyrrolidine-2,3-dione .
user
C20H20N2O4
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