You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[[5-[(1S)-1-amino-2-(1H-indol-3-yl)ethyl]-1,3,4-oxadiazol-2-yl]sulfanyl]-N-(3-chloro-2-methylphenyl)acetamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H20ClN5O2S
assistant