7
0 27 27 23 17 21 21 
27 0 12 10 14 10 10 
27 12 0 8 18 10 10 
23 10 8 0 14 6 6 
17 14 18 14 0 12 8 
21 10 10 6 12 0 4 
21 10 10 6 8 4 0