#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k, a[100], i, j, pre, post, count = 0;
  cin >> n >> k;
  for (i = 0; i < n; i++) cin >> a[i];
  if (n < k)
    cout << -1;
  else {
    sort(a, a + n);
    for (j = n - 1; j >= 0; j--) {
      count++;
      if (count == k) {
        pre = a[j];
        if ((j - 1) < 0)
          post = 0;
        else
          post = a[j - 1];
        break;
      }
    }
    for (i = post; i <= pre; i++) {
      if (i > post && i <= pre) {
        cout << i << " " << i << endl;
        break;
      }
    }
  }
  return 0;
}
