You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named N-(2,5-dimethoxyphenyl)-3-(4-methoxyphenyl)-5-oxo-2H-oxadiazol-3-ium-4-carboximidate by IUPAC nomenclature, provide its molecular formula.
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C18H17N3O6
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