You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
[2-(2-methylpropylamino)-2-oxoethyl] 2-[(4R)-4-methyl-2,5-dioxo-4-(2-phenylethyl)imidazolidin-1-yl]acetate is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H27N3O5
assistant