You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named 4-[[(E)-1-[2-chloro-5-(3-chlorophenyl)-4-hydroxythiophen-3-yl]ethylideneamino]carbamoyl]-2-nitrobenzoic acid by IUPAC nomenclature, provide its molecular formula.
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C20H13Cl2N3O6S
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