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system
Name the molecular formula for the molecule established as methyl (1R,12S,14R,19S)-19-methyl-16-oxo-20-oxa-3,13-diazapentacyclo[11.8.0.02,10.04,9.014,19]henicosa-2(10),4,6,8,17-pentaene-12-carboxylate using the IUPAC nomenclature.
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C21H22N2O4
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