You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N'-[(E)-[4-(1,7-dimethylimidazo[1,2-a]pyridin-4-ium-2-yl)phenyl]methylideneamino]pyrrolidine-1-carboximidamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H25N6+
assistant