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 5-O-methyl 3-O-propan-2-yl 2-methyl-4-(3-nitrophenyl)pyridine-3,5-dicarboxylate is given. What is its corresponding molecular formula?
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C18H18N2O6
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