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