You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named 1-[(6-chloropyridin-3-yl)methyl]-2-methyl-3-[(2-phenyl-1,3-oxazol-4-yl)methyl]guanidine by IUPAC nomenclature, provide its molecular formula.
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C18H18ClN5O
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