You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
4-fluoro-N-[1-[(3S)-1-(5-methyl-1,2-oxazol-3-yl)-2,5-dioxopyrrolidin-3-yl]piperidin-1-ium-4-yl]benzamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H22FN4O4+
assistant