You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named [1-[4-[2-[4-(hydroxyamino)-3-methyl-3-methylsulfonyl-4-oxobutyl]-3-oxo-1H-pyrrolo[1,2-c]imidazol-6-yl]buta-1,3-diynyl]cyclopropyl]methyl hydrogen sulfate by IUPAC nomenclature, provide its molecular formula.
user
C20H23N3O9S2
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