You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 1-[(2-fluorophenyl)methyl]-N-[2-(1H-indol-3-yl)ethyl]pyridin-1-ium-4-carboxamide by IUPAC nomenclature, provide its molecular formula.
user
C23H21FN3O+
assistant