7
0 15 15 12 9 12 12 
15 0 6 7 10 7 7 
15 6 0 3 10 3 3 
12 7 3 0 9 2 2 
9 10 10 9 0 9 7 
12 7 3 2 9 0 2 
12 7 3 2 7 2 0