You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
5-[3-[(E)-2-phenylethenyl]-1H-indol-2-yl]-3-pyridazin-4-yl-1H-pyridazin-6-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C24H17N5O
assistant