$(8$ points$)$ Show that the language

$L_1=\{\begin{array}{ccc}{1}^{k}y\text{:}\text{y}\text{i}\text{n}& \{0,& 1{\}}^{**}\end{array}$ and $y$ contains at most $k1s,$ for $\{$:$k1\}$ is not regular.

No ai please