7
0 25 21 17 13 18 17 
25 0 10 10 12 7 8 
21 10 0 8 14 7 8 
17 10 8 0 12 5 6 
13 12 14 12 0 9 6 
18 7 7 5 9 0 3 
17 8 8 6 6 3 0