#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k;
  while (cin >> n >> k) {
    vector<int> v(n + 1);
    for (int i = 0; i < n; ++i) cin >> v[i];
    v[n] = 0;
    sort(v.rbegin(), v.rend());
    if (k < v.size()) {
      printf("%d %d\n", v[k - 1], v[k - 1]);
    } else {
      printf("-1\n");
    }
  }
  return 0;
}
