You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named (2S,3S,5S)-5-[(1-amino-3-methyl-1-oxobutan-2-yl)carbamoyl]-3-methyloxolane-2-carboxylic acid by IUPAC nomenclature, provide its molecular formula.
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C12H20N2O5
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