You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named 3,5-diamino-6-chloro-N-[(1,3-dimethylbenzimidazol-3-ium-2-yl)methyl]pyrazine-2-carboxamide by IUPAC nomenclature, provide its molecular formula.
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C15H17ClN7O+
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