4, 6, 8, 10, 12, 14, 16, 18
1, 2, 4, 6, 8, 10, 12, 14, 16, 18
6, 8, 10, 12, 14, 16, 18
1, 2
14, 16, 18
8, 10, 12, 14, 16, 18
1, 2, 3, 4