You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Under IUPAC nomenclature, a molecule named 2-(2-methylbenzimidazol-1-yl)-1-[4-(pyridin-4-ylmethyl)-1,4-diazepan-1-yl]ethanone is given. What is its corresponding molecular formula?
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C21H25N5O
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