20
15 12 20 19 18 13 11 14 16 17 
19 11 20 15 16 17 12 14 18 13 
20 12 19 17 18 13 14 16 15 11 
19 13 11 18 12 14 17 16 15 20 
18 13 19 20 16 15 11 12 17 14 
15 18 11 12 13 17 14 20 16 19 
12 11 17 18 13 16 15 20 14 19 
11 19 13 14 12 16 15 20 18 17 
17 15 14 20 11 19 16 13 12 18 
20 17 18 13 11 14 16 19 15 12 
9 6 3 2 1 5 10 7 4 8 
7 9 10 1 2 8 6 5 3 4 
2 7 9 4 10 1 5 8 6 3 
4 5 3 2 1 7 6 9 10 8 
9 4 7 8 1 3 10 6 2 5 
9 4 3 6 5 8 2 10 1 7 
3 10 2 6 7 1 8 9 4 5 
4 7 10 9 2 8 3 5 1 6 
10 4 3 7 6 1 9 2 5 8 
1 5 4 3 10 8 7 9 2 6 
forbidden 1 12
forbidden 1 17
forbidden 1 19
forbidden 1 20
forbidden 2 11
forbidden 2 14
forbidden 2 15
forbidden 2 17
forbidden 2 19
forbidden 3 11
forbidden 3 19
forbidden 3 20
forbidden 4 17
forbidden 4 18
forbidden 5 12
forbidden 5 16
forbidden 5 18
forbidden 6 11
forbidden 6 14
forbidden 6 17
forbidden 6 18
forbidden 6 19
forbidden 6 20
forbidden 7 11
forbidden 7 13
forbidden 7 18
forbidden 8 11
forbidden 8 16
forbidden 8 18
forbidden 8 19
forbidden 9 12
forbidden 9 13
forbidden 9 15
forbidden 9 16
forbidden 9 18
forbidden 10 12
forbidden 10 13
forbidden 10 14
forbidden 10 16