You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
11-phenyl-4,8,11-triaza-1-azoniapentacyclo[10.7.0.02,10.04,9.013,18]nonadeca-1(12),2,5,7,9,13,15,17-octaene The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H15N4+
assistant