Exercise $3\mathrm{.}2\mathrm{.}6$ Devise a programmable Turing Machine which computes

$f(x)=\{\begin{array}{ccc}x& ifxis\text{a}\text{m}\text{u}\text{l}\text{t}\text{i}\text{p}\text{l}\text{e}of& 3\\ 0& \text{o}\text{t}\text{h}\text{e}\text{r}\text{w}\text{i}\text{s}\text{e}\text{.}& \end{array}$