You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Convert the IUPAC name of a molecule 2-O-tert-butyl 7a-O-ethyl (3aS,7aR)-3,3a,4,5,6,7-hexahydro-1H-pyrrolo[3,4-c]pyridine-2,7a-dicarboxylate into molecular formula.
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C15H26N2O4
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