You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(3R,4S,4aS,9bS)-3-[3-ethoxypropyl(2-oxobutanoyl)amino]-8-formyl-4-hydroxy-N-(2-hydroxyethyl)-6-methoxy-3,4,4a,9b-tetrahydrodibenzofuran-1-carboxamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C26H34N2O9
assistant