function ret=mark_proper(ind,sig)
ret=[];
if isempty(sig),ret=ind;disp(' EMPTY ');return; end
kk=1;

for ii=1:length(ind)
    if(sum([sig==ind(ii)])==0)
        ret(kk)=ind(ii);
        kk=kk+1;
    end
end

if isempty(ret),ret=[];end