A:=[ [ 5, 2,-1, 3, 4,-6], 
     [ 5, 3 -6, 4, 1, 2], 
     [ 3, 4 -2, 1, 5, 6], 
     [-6, 1,-5, 4, 2, 3], 
     [ 3,-2, 1, 6,-5, 4]]: