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