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 tert-butyl N-[4a-(2-fluoro-5-nitrophenyl)-2-methyl-1-oxo-5,6,7,7a-tetrahydrocyclopenta[e][1,2,4]thiadiazin-3-yl]carbamate is given. What is its corresponding molecular formula?
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C18H23FN4O5S
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