# 3-Approximation for General position subset

I am currently studying for an exam and stumbled upon the following task: Given the following problem:

Input A set of points $$P \subseteq \mathcal{Q}^2$$ and $$k \in \mathbb{N}$$

Question Find the maximum subset $$S \subseteq P$$ such that no three points in $$S$$ are collinear.

The task is to find a polynomial time 3-approximation algorithm that is an algorithm that deletes at most $$3$$-times as many points as an optimal solution. Unfortunately, I am totally clueless here. How would such an algorithm look like?