You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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N-[4-chloro-1-[(2-chlorophenyl)methyl]pyrazol-3-yl]-3-(1H-indol-3-yl)propanamide is the IUPAC name of a molecule. Please give its molecular formula.
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C21H18Cl2N4O
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