You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-(cyclohexylamino)-3-methyl-2-propyl-5H-pyrido[1,2-a]benzimidazol-10-ium-4-carbonitrile is the IUPAC name of a molecule. Please give its molecular formula.
user
C22H27N4+
assistant