You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named [2-(2-methyl-1H-indol-3-yl)-2-oxoethyl] 2-acetamido-4,5-dimethylthiophene-3-carboxylate by IUPAC nomenclature, provide its molecular formula.
user
C20H20N2O4S
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