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 1-ethyl-2-[(3-nitrophenyl)methyl]-3-[(3-pentan-3-yl-1,2-oxazol-5-yl)methyl]guanidine into molecular formula.
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C19H27N5O3
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