10 [3]
0 (1) 1   [1]
1 (2) 0 2 [2] 
2 (2) 1 3 [3]
3 (2) 2 4 [1]
4 (2) 3 5 [2]
5 (2) 4 6 [3]
6 (2) 5 7 [1]
7 (2) 6 8 [2]
8 (2) 7 9 [3]
9 (1) 8   [1]