7
0 30 29 24 19 23 23 
30 0 13 12 15 11 11 
29 13 0 9 18 10 10 
24 12 9 0 15 7 7 
19 15 18 15 0 12 8 
23 11 10 7 12 0 4 
23 11 10 7 8 4 0