For nonnegative integer $n$, the following are true: $f(0) = 0$ $f(1) = 1$ $f(n) = f(n-\frac{m(m-1)}{2})-f(\frac{m(m+1)}{2} -n)$ for integer $m$ satisfying $m \ge 2$ and $\frac{m(m-1)}{2} < n \le \frac{m(m+1)}{2}$. Find the smallest $n$ such that $f(n) = 4$.