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 1-[2-[[2-[[(3R)-1-acetylpyrrolidin-3-yl]amino]-5-methylpyrimidin-4-yl]amino]phenyl]but-3-en-2-one into molecular formula.
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C21H25N5O2
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