You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Under IUPAC nomenclature, a molecule named (2R)-2-[(R)-carboxy-[(2-thiophen-2-ylacetyl)amino]methyl]-5-[(E)-2-(2,4-dinitrophenyl)ethenyl]-5,6-dihydro-2H-1,3-thiazine-4-carboxylic acid is given. What is its corresponding molecular formula?
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C21H18N4O9S2
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