You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 3-[(3aR,7aS)-1,3-dioxo-3a,4,7,7a-tetrahydroisoindol-2-yl]-N-(6-amino-1-butyl-2,4-dioxopyrimidin-5-yl)-N-methylpropanamide by IUPAC nomenclature, provide its molecular formula.
user
C20H27N5O5
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