Let $\displaystyle f(x) = \frac{x}{x^2 +2 x +29}.$
A. Find the smallest real number $r$ such that $f(x)$ is decreasing for all $x$ greater than $r.$
$r =$
B. Find the smallest integer $s$ such that $f(n)$ is decreasing for all integers $n$ greater than or equal to $s$.
$s =$