You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule 1-[(2,5-difluorophenyl)methyl]-2-methyl-3-[(6-pyrrolidin-1-ylpyridin-3-yl)methyl]guanidine into molecular formula.
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C19H23F2N5
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