You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
4-(butoxymethyl)-12-chloro-9-phenyl-2,4,5,8,11-pentazatricyclo[8.4.0.02,6]tetradeca-1(10),5,8,11,13-pentaen-3-one The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H20ClN5O2
assistant