7 7
#   i    j    i0   j0   N2   c
1   1    0    0    0    0   -1  
1  -1    0    0    0    1    0  
1   0    1    0    0    0   -1  
1   0   -1    0    0    1    0  
1  -1    1    0    0    0    1  
0  -1    0    1    0    0    0  # i<i0
1   0   -1    0    1    0    0  # j<=j0

4 5
# 1 <= i0,j0 <= N2
1 1 0 0 1
1 -1 0 1 0
1 0 1 0 1
1 0 -1 1 0

i0 j0 N2

