1,1,2,0
2,2,3,0
3,3,4,0
4,4,5,0
5,5,6,0
6,6,7,0
7,7,8,0
8,8,9,0
9,9,10,0
10,10,11,0
11,11,12,0
12,12,13,0
13,13,14,0
14,14,15,0
15,15,16,0
16,16,17,0
17,17,18,0