Let $n$ be a positive integer and
$$
F(x)=\frac{\lfloor x\rfloor}{n}
$$
for $0 \leq x \leq n, F(x)=0$ for $x<0$, and $F(x)=1$ for $x>n$, where $\lfloor x\rfloor$ is the greatest integer less than or equal to $x$. Show that $F$ is a CDF, and find the PMF that it corresponds to.