You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Convert the IUPAC name of a molecule lithium;(3S,6S,7aR)-6-benzyl-6-butyl-7a-methyl-3-propan-2-yl-3,7-dihydro-2H-pyrrolo[2,1-b][1,3]oxazol-5-one into molecular formula.
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C21H30LiNO2
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