You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[[4-methyl-5-[2-oxo-2-[[(1S)-1-phenylethyl]amino]ethyl]sulfanyl-1,2,4-triazol-3-yl]methyl]benzamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H23N5O2S
assistant