You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
5-(2,6-dimethylpyrimidin-4-yl)-1-(2-phenylethyl)-6,7-dihydro-4H-imidazo[4,5-c]pyridine The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H23N5
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