You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
3-(1,4-dioxo-4a,5,8,8a-tetrahydro-3H-phthalazin-2-yl)-N-[2-methyl-1-(4-propan-2-ylphenyl)propyl]benzamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C28H33N3O3
assistant