You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule 4-oxo-4-(6-oxo-5-pyridin-3-yl-7,11-diazatricyclo[7.3.1.02,7]trideca-2,4-dien-11-yl)butanoic acid .
user
C20H21N3O4
assistant