You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(2S)-N-phenyl-2-[4-[3-(trifluoromethyl)phenyl]piperazin-1-ium-1-yl]propanamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H23F3N3O+
assistant