5              :n
13             :nz

1 1 2.0
1 2 -1.0
2 1 -1.0
2 2 2.0
2 3 -1.0
3 2 -1.0
3 3 2.0
3 4 -1.0
4 3 -1.0
4 4 2.0
4 5 -1.0
5 4 -1.0
5 5 2.0        :Matrix

0.0
0.0
0.0
0.0
100.0          :RHS