int A[][] = {{0,  1,  2,  0,  0,  0,  0,  0,  0},
   {1,  0,  3,  0,  0,  0,  0,  0,  0},
   {2,  3,  0,  5,  0,  0,  0,  0,  0},
   {0,  0,  5,  0,  6,  0,  0,  0,  0},
   {0,  0,  0,  6,  0,  0,  8,  0,  1},
   {0,  0,  0,  0,  0,  0,  4,  2,  3},
   {0,  0,  0,  0,  8,  4,  0,  1,  0},
   {0,  0,  0,  0,  0 , 2 , 1 , 0 , 4}, 
   {0,  0,  0,  0,  1,  3,  0,  4,  0}};