8
0 10 7 6 3 16 7 17
17 0 2 11 4 2 13 19
10 12 0 16 18 20 16 18
0 19 2 0 18 4 10 3
3 17 19 4 0 15 8 10
17 12 0 11 19 0 16 0
5 18 18 2 9 12 0 7
16 19 12 12 4 12 15 0