20 12 21
-1 -2
1 -2
1 -10
10 -10
10 -1
2 -1
2 1
10 1
10 10
1 10
1 2
-1 2
-1 10
-10 10
-10 1
-2 1
-2 -1
-10 -1
-10 -10
-1 -10
-10 0
-1 0
-1 -10
0 -10
0 -1
10 -1
10 0
1 0
1 10
0 10
0 1
-10 1
