You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule 2-[[(2S,3S)-2-[[(2S)-2-[[2-[[(2S)-2-[[(2S)-2-aminopropanoyl]amino]-3-methylbutanoyl]amino]acetyl]amino]propanoyl]amino]-3-methylpentanoyl]amino]acetic acid .
user
C21H38N6O7
assistant