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