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