1    2 0 0 0
2    3 0 0 0
3    4 0 0 0
4    0 5 0 6
5    0 6 0 0
6    0 7 0 7
7    0 8 0 8
8    0 9 0 9
9    0 10 0 10
10    11 0 11 18
11    12 0 0 0
12    13 0 0 0
13    14 0 0 0
14    15 0 0 0
15    16 0 0 0
16    0 0 0 0
17    0 0 0 0
18    10 0 19 19
19    0 0 0 0