You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name N-(3,4-difluorophenyl)-4-[6-(4-methylpiperidin-1-yl)pyridazin-3-yl]piperazine-1-carboxamide into its molecular formula.
user
C21H26F2N6O
assistant