7
0 30 27 21 18 22 22 
30 0 15 13 16 12 12 
27 15 0 8 17 9 9 
21 13 8 0 13 5 5 
18 16 17 13 0 12 8 
22 12 9 5 12 0 4 
22 12 9 5 8 4 0