You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
4-(1,1-dimethylinden-2-yl)-7-methyl-6-(1-methylpyridin-1-ium-2-yl)dibenzofuran-3-carbonitrile is the IUPAC name of a molecule. Please give its molecular formula.
user
C31H25N2O+
assistant