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 2-fluoro-5-[[(3R)-3-(2-methyl-4,5,6,7-tetrahydrobenzimidazol-1-yl)pyrrolidin-1-yl]methyl]benzonitrile into its molecular formula.
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C20H23FN4
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