You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
5-O-ethyl 3-O-methyl 2,2-dimethyl-4-[2-(3-nitrooxypropoxy)phenyl]-3,4-dihydro-1H-pyridine-3,5-dicarboxylate is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H28N2O8
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