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 (2R)-N-[(3R)-1-(4-chlorophenyl)-5-oxopyrrolidin-3-yl]-2-methyl-2,3-dihydroindole-1-carboxamide is given. What is its corresponding molecular formula?
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C20H20ClN3O2
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