You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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6-fluoro-2-methyl-N-(2-phenyl-2-pyrrolidin-1-ylethyl)imidazo[1,2-a]pyridine-3-carboxamide The above is the IUPAC name of a molecule. Write its molecular formula.
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C21H23FN4O
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