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-[5-(5-benzyl-1,2-oxazol-3-yl)-3,4-dihydropyridin-6-yl]-1-thiophen-2-ylethanone into molecular formula.
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C21H18N2O2S
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