You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
ethyl 5-amino-2-[(3S,4R)-4-[(3,4-dichloro-5-methyl-1H-pyrrole-2-carbonyl)amino]-3-methoxypiperidin-1-yl]pyridine-4-carboxylate is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H25Cl2N5O4
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