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 N-(7-chloro-4-methyl-1,3-benzothiazol-2-yl)-1-ethyl-5-methyl-N-(pyridin-3-ylmethyl)pyrazole-3-carboxamide into molecular formula.
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C21H20ClN5OS
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