You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
ethyl 5-[2-[2-(2-formylphenoxy)acetyl]oxyacetyl]-2,4-dimethyl-1H-pyrrole-3-carboxylate is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H21NO7
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