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