You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named N-(2,6-dimethylpyrimidin-4-yl)-6-(5-fluoro-2-methylpyridin-4-yl)imidazo[1,2-a]pyrazin-2-amine by IUPAC nomenclature, provide its molecular formula.
user
C18H16FN7
assistant