You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 1-methyl-N-[1-(3-methylbutyl)-2-oxo-3,4-dihydroquinolin-6-yl]-2-oxopyridine-3-carboxamide by IUPAC nomenclature, provide its molecular formula.
user
C21H25N3O3
assistant