You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
16-chloro-3-hydroxy-10,20-diazapentacyclo[11.7.1.02,7.09,21.014,19]henicosa-1(21),2(7),3,5,9,11,13,15,17,19-decaen-8-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H9ClN2O2
assistant