7
0 30 25 21 17 21 21 
30 0 11 11 13 9 9 
25 11 0 8 16 8 8 
21 11 8 0 14 6 6 
17 13 16 14 0 12 8 
21 9 8 6 12 0 4 
21 9 8 6 8 4 0