You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name (7R)-3-(4-chlorophenyl)-7-(3-ethoxyphenyl)-5-oxo-6,7-dihydro-4H-thieno[3,2-b]pyridine-2-carboxylic acid into its molecular formula.
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C22H18ClNO4S
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