function M = length_atmost(k,localf)
sigr = setreg([localf '@']);
reg = repmat(sigr,1,k);
M = gregexp2dfsa_fast(reg,localf);
return


function re = setreg(u)
k=length(u);
P=repmat('+',1,k);
up = [u;P];
up = up(:)';
re = ['(' up(1:end-1) ')'];
return