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