You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
5-[(2R,3S,4R,5R)-6-[[(2S)-2-carboxy-1-[2-(2,6-dicarboxy-2,3-dihydro-1H-pyridin-4-ylidene)ethylidene]-6-hydroxy-2,3-dihydroindol-1-ium-5-yl]oxy]-3,4,5-trihydroxyoxan-2-yl]oxy-5-oxopentanoate The above is the IUPAC name of a molecule. Write its molecular formula.
user
C28H30N2O16
assistant