You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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3-chloro-N-(5-imidazo[1,2-a]pyrimidin-2-yl-2-methoxyphenyl)-4-methylbenzenesulfonamide is the IUPAC name of a molecule. Please give its molecular formula.
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C20H17ClN4O3S
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