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 6-[2-(cyclobutylmethyl)-7H-pyrrolo[2,3-d]pyrimidin-5-yl]-N-(2,2-difluoroethyl)imidazo[1,2-a]pyridine-3-carboxamide into molecular formula.
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C21H20F2N6O
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