You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule 2-[(5-chloro-1,3-benzoxazol-2-yl)sulfanyl]-N-[(3,4-dimethoxyphenyl)methyl]-N-ethylacetamide into molecular formula.
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C20H21ClN2O4S
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