You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
3-[1-(3-chloropyridin-4-yl)piperidin-4-yl]-6-cyclopropyl-[1,2,4]triazolo[4,3-b]pyridazine The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H19ClN6
assistant