7
0 28 27 22 17 21 21 
28 0 13 12 15 11 11 
27 13 0 9 16 10 10 
22 12 9 0 13 7 7 
17 15 16 13 0 10 6 
21 11 10 7 10 0 4 
21 11 10 7 6 4 0