Qn on Pigeon-Hole Principle

Question

Let S be a set of 10 positive integers ≤ 50. Show that there two different (but not necessarily disjoint) subsets of four integers such that the sums of the 4 integers in the sets are equal.

Having problems identifying which should be the pigeon-hole. Would appreciate some help here.. Thanks

Answer 1

Hint: There are $\binom{10}{4}$ different subsets of size four but only $200$ possible sums.