You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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1-[(2-bromophenyl)methyl]-2-[(4,5-dimethyl-1,3-oxazol-2-yl)methyl]-3-ethyl-1-methylguanidine is the IUPAC name of a molecule. Please give its molecular formula.
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C17H23BrN4O
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