You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 2-[(4R)-4-(2-methoxyphenyl)-1-methyl-2,5-dioxo-4,7-dihydro-3H-pyrrolo[3,4-d]pyrimidin-6-yl]-N-(2-methylpropyl)acetamide into its molecular formula.
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C20H26N4O4
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