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