You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Translate the chemical IUPAC name (3-cyanophenyl)methyl (3aR)-4-oxo-2,3,3a,5-tetrahydro-1H-pyrrolo[1,2-a]quinoxaline-7-carboxylate into its molecular formula.
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C20H17N3O3
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