You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule 3-bromo-N-[2-[methyl-[2-oxo-2-(2,4,6-trimethylanilino)ethyl]amino]-2-oxoethyl]benzamide into molecular formula.
user
C21H24BrN3O3
assistant