7
0 21 22 17 12 15 15 
21 0 9 8 11 8 8 
22 9 0 7 12 7 7 
17 8 7 0 9 4 4 
12 11 12 9 0 9 5 
15 8 7 4 9 0 4 
15 8 7 4 5 4 0