You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[7-(hydroxymethyl)-3,5-dihydro-2H-1,4-benzoxazepin-4-yl]-2-[[(2S)-oxan-2-yl]methoxy]ethanone is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H25NO5
assistant