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