You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Convert the IUPAC name of a molecule 2-(3-chloro-4-fluorophenyl)-5-(2,4-dichlorophenyl)-1-ethyl-6-methyl-4-oxopyridine-3-carboxylic acid into molecular formula.
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C21H15Cl3FNO3
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