You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name [2-[(1-cyanocyclopentyl)amino]-2-oxoethyl] 2-(1,3-dioxo-3a,4,7,7a-tetrahydroisoindol-2-yl)acetate into its molecular formula.
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C18H21N3O5
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