International Mathematical Olympiad 1989 Problem 1

Prove that the set $\{1,2,\ldots,1989\}$ can be expressed as the disjoint union of subsets $A_i$ ($i = 1, 2, \ldots, 117$) such that:

(i) Each $A_i$ contains 17 elements;

(ii) The sum of all the elements in each $A_i$ is the same.