function Y = count(X)
%COUNT Frequency of unique rows.
%   Y = COUNT(X) computes the frequency of each unique row of an M-by-N matrix
%   X and returns an M-by-(N+1) matrix Y sorted in ascending order of
%   frequency, whose first column contains the count for the corresponding
%   row of X. 
%
%   Example: 
%   >> count([10 20 30; 40 50 60; 10 20 30])
% 
%   ans =
% 
%      1    40    50    60
%      2    10    20    30

[b,i,j] = unique(X,'rows');
numUniq = size(b,1);
Y = [zeros(numUniq,1), b];
for k = 1:numUniq
    Y(k,1) = sum(j==k); 
end
Y = sortrows(Y);