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