You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[4-(2-benzhydryloxyethyl)piperazin-1-yl]-2-butyl-3-methylpyrido[1,2-a]benzimidazole-4-carbonitrile is the IUPAC name of a molecule. Please give its molecular formula.
user
C36H39N5O
assistant