#include <bits/stdc++.h>
using namespace std;
const int size = 50 + 10;
int n, k, aim[size], num[size], ans = -1;
int main() {
  cin >> n >> k;
  if (k > n) {
    cout << -1 << endl;
    return 0;
  }
  for (int i = 1; i <= n; i++) cin >> aim[i];
  sort(aim + 1, aim + n + 1);
  num[1] = 0;
  for (int i = 2; i <= n; i++)
    if (aim[i] > aim[i - 1])
      num[i] = i - 1;
    else
      num[i] = num[i - 1];
  for (int i = 1; i <= n; i++)
    if (aim[i] != aim[i + 1] && n - num[i] == k) ans = aim[i];
  if (ans < 0) {
    cout << ans << endl;
    return 0;
  }
  cout << ans << " " << ans << endl;
  return 0;
}
