You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[5-[3,3-dimethyl-1-(3-sulfanylidenepropyl)indol-1-ium-2-yl]penta-2,4-dienylidene]-1-ethyl-3,3-dimethylindole-5-sulfonic acid is the IUPAC name of a molecule. Please give its molecular formula.
user
C30H35N2O3S2+
assistant