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 1-[4-[6-(3,5-dimethylpyrazol-1-yl)pyridazin-3-yl]piperazin-1-yl]-2-(2-fluorophenoxy)ethanone .
user
C21H23FN6O2
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