You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance [2-[ethyl-[2-[(4-fluorophenyl)methylamino]-2-oxoethyl]amino]-2-oxoethyl] 3-aminopyrazine-2-carboxylate .
user
C18H20FN5O4
assistant