You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(1R,9S,12R)-N,N-diethyl-9,10-dimethyl-11-oxo-8-oxa-10-azatricyclo[7.3.1.02,7]trideca-2,4,6-triene-12-carboxamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H24N2O3
assistant