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 2-[1-(4-chlorophenyl)-3,5-dimethylpyrazol-4-yl]-N-[2-[(3-cyanopyridin-2-yl)amino]ethyl]acetamide into molecular formula.
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C21H21ClN6O
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