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 ethane;13-pyridin-4-yl-4,10,12,15-tetraza-1-azoniatricyclo[7.7.0.03,7]hexadeca-1,5,8,10,13,15-hexaene .
user
C18H21N6+
assistant