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-(4-bromophenyl)-N-(4-chloro-2-methoxy-5-methylphenyl)-6-methylthieno[2,3-d]pyrimidin-4-amine is given. What is its corresponding molecular formula?
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C21H17BrClN3OS
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