You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
7,9-difluoro-2,5-dimethylimidazo[5,1-a]isoindol-4-ium-5-ide;2,5-dimethylimidazo[5,1-a]isoindol-4-ium-5-ide;5-methyl-2-phenylimidazo[5,1-a]isoindol-4-ium-5-ide;yttrium is the IUPAC name of a molecule. Please give its molecular formula.
user
C41H36F2N6Y3
assistant