You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Under IUPAC nomenclature, a molecule named 2-[2-(5-methoxycarbonyl-11-methylpyrido[4,3-b]carbazol-2-yl)ethylamino]ethylazanium is given. What is its corresponding molecular formula?
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C22H25N4O2+
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