6, 7, 8, 9
1, 2
5, 6, 7, 8
6, 7, 8
1, 2, 3
16, 17, 18
17
3, 4, 5, 6, 7, 8, 9, 10, 11, 12
1, 2, 3, 4
1, 2, 3, 4, 5, 6
