You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance 2-(2,2-dimethyl-1,3-dihydrobenzo[f]isoquinolin-3-ium-4-ylidene)-1-pyrrolidin-1-ylethanone;chloride .
user
C21H25ClN2O
assistant