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-chloro-2-(6-chloro-4-oxo-4a,8a-dihydro-3H-quinazolin-2-yl)phenyl] piperidine-1-carboxylate .
user
C20H19Cl2N3O3
assistant