You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named [(2S)-1-(2-chloroanilino)-1-oxopropan-2-yl] 5-ethoxy-3-methyl-1-benzofuran-2-carboxylate by IUPAC nomenclature, provide its molecular formula.
user
C21H20ClNO5
assistant