You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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4-[7-[(3S)-3-methyl-4-oxopentanoyl]-4-oxo-3,5,6,8-tetrahydropyrido[3,4-d]pyrimidin-2-yl]benzamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H22N4O4
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