You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named N-[2-(3-fluorophenoxy)ethyl]-1-(3-methylphenyl)-6-oxo-4,5-dihydropyridazine-3-carboxamide by IUPAC nomenclature, provide its molecular formula.
user
C20H20FN3O3
assistant