You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 2-[2-[4-(2-methylpyridin-4-yl)piperazin-1-yl]ethyl]-6,7-dihydro-5H-cyclopenta[c]pyridazin-3-one into its molecular formula.
user
C19H25N5O
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