You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 9,10-dimethyl-N-(3-nitrophenyl)-11-oxo-8-oxa-10-azatricyclo[7.3.1.02,7]trideca-2,4,6-triene-12-carboxamide by IUPAC nomenclature, provide its molecular formula.
user
C20H19N3O5
assistant