%%MatrixMarket matrix coordinate real symmetric
%  2   3   0   0   0
%  3   0  -1   0   6
%  0  -1   0   2   0
%  0   0   2   3   0
%  0   6   0   0   1
5 5 7
  1 1  2
  2 1  3
  3 2 -1
  4 3  2
  4 4  3
  5 2  6
  5 5  1