#include <bits/stdc++.h>
using namespace std;
int main() {
  int a[60], i, x, n, k;
  cin >> n >> k;
  for (i = 1; i <= n; i++) cin >> a[i];
  sort(a + 1, a + 1 + n);
  if ((n + 1 - k) >= 1)
    cout << a[n + 1 - k] << " " << a[n + 1 - k];
  else
    cout << "-1";
}
