#include <bits/stdc++.h>
using namespace std;
const int Maxn = 40;
int n, k;
vector<int> num;
void input() {
  cin >> n >> k;
  int a;
  for (int i = 0; i < n; i++) {
    cin >> a;
    num.push_back(a);
  }
}
void output() {
  sort(num.begin(), num.end());
  if (k <= n)
    cout << num[n - k] << " " << num[n - k] << endl;
  else
    cout << "-1" << endl;
}
int main() {
  input();
  output();
  return 0;
}
