Solution (source code)

= Solution

The number of stops is $X\sim\operatorname{Bin}(n,1/n)$. For each fixed $k\ge0$,
$$
\mathbb P(X=k)=\binom nk n^{-k}(1-n^{-1})^{n-k}\longrightarrow\frac{e^{-1}}{k!},
$$
the mass <function> of a Poisson <random variable> of mean one.