18
0 1 0 0
1 0 0 0
1 1 0 1
1 1 1 1
1 2 1 2
2 2 0 2
2 1 1 0
0 0 0 1
0 0 0 2
0 0 1 0 
0 0 1 2
0 1 0 2
0 1 1 0
0 1 1 1
1 0 1 1
1 0 1 2
1 2 0 1
1 2 0 0
