0 1 1
0 2 2
0 3 3
0 4 4
0 6 5
0 7 6
0 8 7
0 9 8
0 10 9
0 11 10
0 12 11
0 13 12
0 14 13
0 15 14
0 16 15
0 17 16
0 18 17
0 19 18
0 20 19
0 21 20
13 0 27
10 0 21
5 0 22
1 0 23
2 0 24
3 0 25
7 0 26
