You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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(1S,2R)-2-[(2-methyl-5-phenylpyrazolo[1,5-a]pyrimidin-7-yl)amino]cyclopentane-1-carboxamide is the IUPAC name of a molecule. Please give its molecular formula.
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C19H21N5O
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