You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
ethyl (6R)-3-ethyl-4-[(4-ethylpiperazin-1-yl)methyl]-2-oxo-6-phenyl-1,6-dihydropyrimidine-5-carboxylate is the IUPAC name of a molecule. Please give its molecular formula.
user
C22H32N4O3
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