You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
3-[(2R)-1-(3-propan-2-yl-3,6-diazabicyclo[3.2.0]heptan-6-yl)propan-2-yl]-3,7-diazabicyclo[3.3.1]nonane is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H34N4
assistant