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 [(2S)-2-(aminomethyl)pyrrolidin-1-yl]-[3-(4-chloroanilino)-5-[(5-methyl-1H-pyrazol-3-yl)amino]pyrazin-2-yl]methanone into molecular formula.
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C20H23ClN8O
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