You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Under IUPAC nomenclature, a molecule named N-(1,2,3,5,6,7,8,8a-octahydroindolizin-7-yl)-1-cycloheptyl-5-oxopyrrolidine-3-carboxamide is given. What is its corresponding molecular formula?
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C20H33N3O2
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