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