You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(2S)-2-[[5-[ethyl(pyridine-4-carbonyl)amino]pyrimidin-4-yl]amino]-3-[4-[methyl-[3-(methylamino)pyridin-2-yl]amino]phenyl]propanoic acid is the IUPAC name of a molecule. Please give its molecular formula.
user
C28H30N8O3
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