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