You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Name the molecular formula for the molecule established as (2S)-N-(4-acetamidophenyl)-2-(3-oxo-2,5,7,8-tetrahydropyrido[4,3-c]pyridazin-6-yl)propanamide using the IUPAC nomenclature.
user
C18H21N5O3
assistant