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