#include <bits/stdc++.h>
using namespace std;
int compare(const void* a, const void* b) { return (*(int*)a - *(int*)b); }
int main() {
  int n, k, ans = -1;
  cin >> n >> k;
  int a[n];
  for (int i = 0; i < n; i++) cin >> a[i];
  qsort(a, n, sizeof(int), compare);
  if (k <= n) {
    ans = a[n - k];
    cout << ans << " " << ans;
  } else
    cout << "-1";
  return 0;
}
