You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
6-[(5-chlorothiadiazol-4-yl)methyl]-2-methyl-7,8-dihydro-5H-pyrido[4,3-c]pyridazin-3-one The above is the IUPAC name of a molecule. Write its molecular formula.
user
C11H12ClN5OS
assistant