You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 1-ethyl-3-(4-hydroxycyclohexyl)-2-[(6-propan-2-yloxypyridin-3-yl)methyl]guanidine;hydroiodide into its molecular formula.
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C18H31IN4O2
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