You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(8E)-3,14-dioxa-18-azabicyclo[14.3.1]icosa-1(20),8,16,18-tetraene-2,15-dione is the IUPAC name of a molecule. Please give its molecular formula.
user
C17H21NO4
assistant