20
0 0 0 0
1 0 0 0
0 1 0 0
1 1 0 0
0 0 1 0
1 0 1 0
0 1 1 0
1 1 1 0
0 0 0 1
1 0 0 1
2 1 0 1
2 2 0 1
2 0 1 1
2 0 2 1
2 1 0 2
2 0 1 2
0 1 1 2
1 1 1 2
2 2 1 2
2 1 2 2
