You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Convert the IUPAC name of a molecule 3-O-ethyl 6-O-methyl 2-[(5-nitro-1-benzothiophene-2-carbonyl)amino]-5,7-dihydro-4H-thieno[2,3-c]pyridine-3,6-dicarboxylate into molecular formula.
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C21H19N3O7S2
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