#include <bits/stdc++.h>
using namespace std;
int n, k;
int a[55];
void scan(void) {
  cin >> n >> k;
  for (int i = (0); i < (n); i++) cin >> a[i];
}
void solve(void) {
  sort(a, a + n);
  if (k > n)
    cout << "-1\n";
  else
    cout << a[n - k] << " " << a[n - k] << "\n";
}
int main(void) {
  scan();
  solve();
  return 0;
}
