You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance 1-[2-[[2-[(2-amino-4-methylpentanoyl)amino]-4-methylpentanoyl]amino]propanoyl]pyrrolidine-2-carboxylic acid .
user
C20H36N4O5
assistant