Clipped maximum equal to clipped minimum on a grid

Integers $x$ and $y$ are each chosen independently and uniformly from $\{-10,-9,\dots,9,10\}$. Find the probability that $\max(0,x)=\min(0,y)$.

$\tfrac{121}{441}$. The left side is at least $0$ and the right side is at most $0$, so both must equal $0$, which means $x\le0$ and $y\ge0$. Each has $11$ of $21$ possible values, giving $\left(\tfrac{11}{21}\right)^2=\tfrac{121}{441}$.