You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Under IUPAC nomenclature, a molecule named tert-butyl N-[2-[2-(5-ethyl-1H-imidazol-2-yl)-2,3-dihydroindol-1-yl]-2-oxoethyl]carbamate is given. What is its corresponding molecular formula?
user
C20H26N4O3
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