You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
4-[4-amino-3-(1H-indol-2-yl)imidazo[1,5-a]pyrazin-4-ium-1-yl]cyclohexane-1-carboxamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H23N6O+
assistant