7
0 25 25 20 16 21 21 
25 0 10 9 13 8 8 
25 10 0 7 15 8 8 
20 9 7 0 12 5 5 
16 13 15 12 0 11 7 
21 8 8 5 11 0 4 
21 8 8 5 7 4 0