You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
6-chloro-3-(3-chloro-4-iodophenyl)-7,8-dimethyl-[1,2,4]triazolo[4,3-b]pyridazine is the IUPAC name of a molecule. Please give its molecular formula.
user
C13H9Cl2IN4
assistant