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