International Mathematical Olympiad 1982 Problem 1

The function $f(n)$ is defined for all positive integers $n$ and takes on non-negative integer values. Also, for all $m, n$

$$f(m + n) - f(m) - f(n) = 0 \text{ or } 1$$

$$f(2) = 0, f(3) > 0, \text{ and } f(9999) = 3333.$$

Determine $f(1982)$.