7
0 27 25 22 17 21 21 
27 0 12 11 14 10 10 
25 12 0 7 14 8 8 
22 11 7 0 11 5 5 
17 14 14 11 0 10 6 
21 10 8 5 10 0 4 
21 10 8 5 6 4 0