You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance 4-(3-acetyl-5-ethoxy-2-methyl-3,4-dihydropyrido[2,3-d]pyridazin-4-yl)-3-methoxybenzonitrile .
user
C20H20N4O3
assistant