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