construct/nppc three coloring

construct/nppc three coloring: a task in MathConstructOptimize-Envs-harbor (Harbor dataset). Graph with 30 vertices labelled 0..29 and edge list 0, 4 , 0, 8 , 0, 21 , 1, 20 , 1, 24 , 2, 4 , 2, 8 , 2, 14 , 2, 20 , 2, 28 , 3, 6 , 3, 8 , 3, 14 , 3, 15 , 3, 16 , 4, 9 , 4, 11 , 4, 16 , 5, 12 , 5, 29 …