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 2-[4-(6,7-dimethoxy-3,4-dihydro-1H-isoquinolin-2-yl)-4-oxobutyl]-1-(4-methylphenyl)guanidine;hydroiodide into molecular formula.
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C23H31IN4O3
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