You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
methyl (2S)-2-[[(2S)-2-[(4-methoxybenzoyl)amino]-4-methylpentanoyl]amino]-4-methylsulfanylbutanoate is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H30N2O5S
assistant