The complex numbers $a$ and $b$ satisfy
\[a \overline{b} = -1 + 5i.\]Find $\overline{a} b.$
I know that the complex conjugate of a complex number $z = x + yi$ is $\overline{z} = x - yi.$ So, if I take the complex conjugate of both sides of the given equation, I get
\[\overline{a \overline{b}} = \overline{-1 + 5i}.\] Now, I can use the property that the complex conjugate of a product is the product of the complex conjugates, and simplify the right-hand side. This gives me
\[\overline{a} b = -1 - 5i.\] 