6 8
#  i  j  k  l   P  Q
0  3  0  2  1  -1  0   0	# 3i + 2k + l = P
0  4 -1  3  2   0 -1   0	# 4i - j + 3k + 2l = Q
1  1  0  0  0   0  0   0
1  0  1  0  0   0  0   0	# i,j,k,l >= 0
1  0  0  1  0   0  0   0
1  0  0  0  1   0  0   0

2 4
1  1  0   0		# P,Q >= 0
1  0  1   0

P Q
ISNM2 example