3 4
1   1    1   -2
1  -1    1    2
1   0   -1    2

3 4
1   0    1   -1
1   1   -1    1
1  -1   -1    5

6 4
1  -1    0    4
1   1    0    0
1   1    2   -2
1  -1    2    2
1   1   -2    4
1  -1   -2    8