You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule 5-chloro-N-[2-[[3-(3-fluorophenyl)-[1,2,4]triazolo[4,3-b]pyridazin-6-yl]oxy]ethyl]-4-methoxy-2-methylbenzenesulfonamide .
user
C21H19ClFN5O4S
assistant