#include <bits/stdc++.h>
using namespace std;
long arr[55];
int main() {
  int n, k;
  cin >> n >> k;
  for (int i = 0; i < n; i++) cin >> arr[i];
  if (n < k)
    cout << "-1";
  else if (n == k)
    cout << "1 1";
  else {
    sort(arr, arr + n);
    cout << arr[n - k] << " " << arr[n - k];
  }
  return 0;
}
