You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Under IUPAC nomenclature, a molecule named 1-(2,4-dichlorophenyl)-3-[3-(3-pyridin-3-yl-[1,2,4]triazolo[4,3-b]pyridazin-6-yl)phenyl]urea is given. What is its corresponding molecular formula?
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C23H15Cl2N7O
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