7
0 23 21 18 12 15 15 
23 0 10 9 13 10 10 
21 10 0 5 15 8 8 
18 9 5 0 12 5 5 
12 13 15 12 0 11 7 
15 10 8 5 11 0 4 
15 10 8 5 7 4 0