You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
[(2R)-1-[(2-acetyl-1-benzofuran-3-yl)amino]-1-oxopropan-2-yl] 3-aminopyrazine-2-carboxylate is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H16N4O5
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