You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named ethyl 2-[methylidene-(4-methylphenyl)-oxo-lambda6-sulfanyl]oxyimino-2-(4-nitrophenyl)sulfanylacetate by IUPAC nomenclature, provide its molecular formula.
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C18H18N2O6S2
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