You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-(2-oxo-1-azatricyclo[7.3.1.05,13]trideca-5,7,9(13)-trien-7-yl)-1,3-benzodioxole-5-carboxamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H18N2O4
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