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