You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[6-amino-4-[[6-(2,5-dihydroxypyrrol-1-yl)oxy-6-oxohexyl]sulfamoyl]-3-iminoxanthen-9-yl]benzoic acid is the IUPAC name of a molecule. Please give its molecular formula.
user
C30H28N4O9S
assistant