find missing element between two matrix

>> A = [1,2;3,6;3,5;1,4;4,6;2,7;1,6;6,5;2,3;6,7;3,4];
>> B = [1,2;1,6;2,3;3,4;4,6];
>> R = setdiff(A,B,'rows')
R =
   1   4
   2   7
   3   5
   3   6
   6   5
   6   7

To get the same order, use the 'stable' option or this:

>> [~,X] = setdiff(A,B,'rows');
>> X = sort(X);
>> R = A(X,:)
R =
   3   6
   3   5
   1   4
   2   7
   6   5
   6   7