You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[[6-amino-2-[[6-amino-2-[(2-amino-3-sulfanylpropanoyl)amino]hexanoyl]amino]hexanoyl]amino]-3-(1H-imidazol-5-yl)propanoic acid The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H38N8O5S
assistant