You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[[(2R)-1-amino-3-methyl-1-oxobutan-2-yl]amino]-6-oxo-4-(3-pyrimidin-2-ylanilino)-1H-pyrimidine-5-carboxamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H22N8O3
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