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