\bigl|u^{-1}[\{u(m)\}]\bigr|=\left\{\begin{array}{ll}0,&\hbox{za }m\leq 0\hbox{ (ovaj slu\v caj nas i ne zanima, ali neka stoji ovde)}\\1,&\hbox{za }0<m\leq 1\hbox{ ili }m=e\\2,&\hbox{za }1<m\not=e\end{array}\right.