You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
4-[1-(3-chlorophenyl)pyrazol-4-yl]-N-[[(3R)-oxan-3-yl]methyl]pyrimidin-2-amine is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H20ClN5O
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