function S=range_extraction(L)
    % Range extraction
    L(end+1) = NaN;
    S = int2str(L(1));
    k = 1;
    while (k < length(L)-1)
        if (L(k)+1==L(k+1) && L(k)+2==L(k+2) )
            m = 2;
            while (L(k)+m==L(k+m))
                m = m+1;
            end
            k = k+m-1;
            S = [S,'-',int2str(L(k))];
        else
            k = k+1;
            S = [S,',',int2str(L(k))];
        end 	
    end
end

disp(range_extraction([0,  1,  2,  4,  6,  7,  8, 11, 12, 14, 15, ...
                       16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, ...
                       28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39]))