#include <bits/stdc++.h>
using namespace std;
struct multidebug {
  template <typename T>
  multidebug& operator,(const T& v) {
    cerr << v << " ";
    return *this;
  }
} mdbg;
template <class T>
ostream& operator<<(ostream& o, const vector<T>& v) {
  if (v.size() == 0) return o << "{}";
  o << "{";
  for (typeof((v).begin()) it = (v).begin(); it != (v).end(); ++it)
    o << *it << " ";
  return o << "\b}";
}
template <class T>
ostream& operator<<(ostream& o, const set<T>& v) {
  if (v.size() == 0) return o << "{}";
  o << "{";
  for (typeof((v).begin()) it = (v).begin(); it != (v).end(); ++it)
    o << *it << " ";
  return o << "\b}";
}
template <class A, class B>
ostream& operator<<(ostream& o, const map<A, B>& v) {
  if (v.size() == 0) return o << "{}";
  o << "{";
  for (typeof((v).begin()) it = (v).begin(); it != (v).end(); ++it)
    o << *it << " ";
  return o << "\b}";
}
template <class A, class B>
ostream& operator<<(ostream& o, const pair<A, B>& p) {
  o << "(" << p.first << "," << p.second << ")";
  return o;
}
template <class T>
void debugarr(T* v, int n) {
  cerr << "{";
  for (int i = 0; i < n; i++) cerr << v[i] << " ";
  cerr << "\b}" << endl;
}
using namespace std;
int main() {
  int n, k, siz, temp;
  vector<int> v;
  scanf("%d", &n);
  scanf("%d", &k);
  for (int i = 0; i <= (int)n - 1; i++) {
    scanf("%d", &temp);
    v.push_back(temp);
  }
  sort(v.begin(), v.end());
  siz = v.size();
  if (k <= v.size())
    cout << v.at(v.size() - k) << " " << v.at(v.size() - k);
  else
    cout << "-1";
}
