You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-(4-benzoylphenoxy)-1-[(2S)-2-methyl-3,4-dihydro-2H-1,5-benzothiazepin-5-yl]ethanone is the IUPAC name of a molecule. Please give its molecular formula.
user
C25H23NO3S
assistant