Finding the Inverse Function Graphically

Let $f$ be a real function that has an inverse $g$. Suppose the graph $y = f(x)$ contains $5$ lattice points $(a,b)$ with $0 \le a,b\le 10$. How many lattice points $(c,d)$ with $0\le c,d\le 10$ does the graph $y = g(x)$ contain?