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