#include <bits/stdc++.h>
using namespace std;
int main() {
  int num, k;
  cin >> num >> k;
  int arr[num];
  int j;
  for (j = 0; j < num; j++) {
    cin >> arr[j];
  }
  if (k > num)
    cout << -1;
  else {
    sort(arr, arr + num);
    cout << arr[num - k] << " " << arr[num - k];
  }
  return 0;
}
