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 3-[(4R,7S,8aS)-7-[(4-fluorophenyl)sulfonylamino]-1-oxo-3,4,6,7,8,8a-hexahydro-2H-pyrrolo[1,2-a]pyrazin-4-yl]-N-benzylpropanamide into molecular formula.
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C23H27FN4O4S
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