You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
diethyl 4-(1-ethylpyrazol-4-yl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H25N3O4
assistant