2, 3, 7 1, 3, 7 1, 2, 7 8, 10, 14 - 12, 16, 20 1, 2, 3 4, 10, 14 - 4, 8, 14 - 6, 16, 20 - 4, 8, 10 - 6, 12, 20 - - - 6, 12, 16