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 (2S)-2-[[5-[2-[(6S)-2-amino-4-oxo-3,6,7,8-tetrahydropyrimido[5,4-b][1,4]thiazin-6-yl]ethyl]-4-methylthiophen-2-yl]amino]pentanedioic acid is given. What is its corresponding molecular formula?
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C18H23N5O5S2
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