You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
[1-[(2-cyano-3-methylbutan-2-yl)amino]-1-oxopropan-2-yl] (E)-3-(3-nitrophenyl)prop-2-enoate The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H21N3O5
assistant