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-[(4-methoxyphenyl)methyl]-2-methyl-3,4,5,6,7,8-hexahydro-1H-isoquinolin-2-ium is given. What is its corresponding molecular formula?
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C18H26NO+
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