You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-methyl-2-(4-oxo-2,3-dihydro-1,5-benzoxazepin-5-yl)-N-[[4-(trifluoromethyl)phenyl]methyl]acetamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H19F3N2O3
assistant