You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[[4-[[4-(4-chloro-N-methylanilino)pyridin-1-ium-1-yl]methyl]phenyl]methyl]-N,N-dimethylpyridin-1-ium-4-amine;dibromide is the IUPAC name of a molecule. Please give its molecular formula.
user
C27H29Br2ClN4
assistant