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 (2R)-2-(2,5-dichloro-N-methylsulfonylanilino)-N-[4-(pyridin-3-ylsulfamoyl)phenyl]propanamide into molecular formula.
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C21H20Cl2N4O5S2
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