3H-?Indolium, 2-?[7-?[1-?[6-?[[2-?(2,?5-?dihydro-?2,?5-?dioxo-?1H-?pyrrol-?1-?yl)?ethyl]?amino]?-?6-?oxohexyl]?-?1,?3-?dihydro-?3,?3-?dimethyl-?5-?sulfo-?2H-?indol-?2-?ylidene]?-?1,?3,?5-?heptatrien-?1-?yl]?-?1-?ethyl-?3,?3-?dimethyl-?5-?sulfo-?, inner salt