7
0 22 23 20 13 18 18 
22 0 9 8 13 8 8 
23 9 0 7 12 7 7 
20 8 7 0 9 4 4 
13 13 12 9 0 9 5 
18 8 7 4 9 0 4 
18 8 7 4 5 4 0