#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k;
  cin >> n >> k;
  vector<int> v(n);
  for (int i = 0; i < n; ++i) cin >> v[i];
  sort(v.begin(), v.end());
  if (n < k)
    cout << "-1" << endl;
  else
    cout << v[v.size() - k] << ' ' << v[v.size() - k] << endl;
}
