You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[(4-chlorophenyl)methyl]-6-(1H-pyrrolo[2,3-b]pyridin-3-ylmethyl)pyridazin-3-amine The above is the IUPAC name of a molecule. Write its molecular formula.
user
C19H16ClN5
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