You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(1S)-N-(6-cyano-1-cyclobutylbenzimidazol-2-yl)-2,2-dimethylcyclopropane-1-carboxamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H20N4O
assistant