Question 108
Let $\mathbb{Z}$ be the set of all integers. Determine all functions $f : \mathbb{Z} \to \mathbb{Z}$ such that
$$
f(x - f(y)) = f(f(x)) - f(y) - 1
$$
holds for all $x, y \in \mathbb{Z}$.
$$
f(x - f(y)) = f(f(x)) - f(y) - 1
$$
holds for all $x, y \in \mathbb{Z}$.