You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 7-[(1S)-1-aminoethyl]-6-methoxy-1-(3-methoxypropyl)-4,4-dimethyl-3H-quinolin-2-one by IUPAC nomenclature, provide its molecular formula.
user
C18H28N2O3
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