You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Can you give the molecular formula of the molecule ethyl 6-butyl-4-(3-ethoxy-4-methoxy-5-nitrophenyl)-2-oxo-3,4-dihydro-1H-pyrimidine-5-carboxylate ?
user
C20H27N3O7
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