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 3-[2-[4-(aminomethyl)-2-methylpyrrolidin-1-yl]-2-oxoethyl]-1H-benzimidazol-2-one;hydrochloride into its molecular formula.
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C15H21ClN4O2
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