You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named (3S)-1-(4-fluorophenyl)-3-[(3S)-3-methylpiperidin-1-ium-1-yl]pyrrolidine-2,5-dione by IUPAC nomenclature, provide its molecular formula.
user
C16H20FN2O2+
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