You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(2S)-2-[[(2R)-4-methyl-2-[[(2S)-3-oxo-2-propan-2-yl-2,4-dihydroquinoxaline-1-carbonyl]amino]pentanoyl]amino]-3-phenylpropanoic acid is the IUPAC name of a molecule. Please give its molecular formula.
user
C27H34N4O5
assistant