You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named 4-[(1R)-1-(3-cyclopropyl-6-pyridin-2-ylbenzimidazol-4-yl)oxyethyl]pyrrolidin-2-one by IUPAC nomenclature, provide its molecular formula.
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C21H22N4O2
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