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 7-bromo-4-[[5-chloro-1-(2-methoxyethyl)benzimidazol-2-yl]sulfanylmethyl]chromen-2-one into molecular formula.
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C20H16BrClN2O3S
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