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 N-[2-[6-[(4-fluorophenyl)methylamino]-[1,2,4]triazolo[4,3-b]pyridazin-3-yl]ethyl]-4-methylbenzenesulfonamide .
user
C21H21FN6O2S
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