You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-(3,4-dimethylphenyl)-4-oxo-1-azatricyclo[7.3.1.05,13]trideca-2,5,7,9(13)-tetraene-3-carboxamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H20N2O2
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