You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[4-(3-pyridin-4-yl-[1,2,4]triazolo[4,3-b]pyridazin-6-yl)phenyl]acetamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H14N6O
assistant