#include <bits/stdc++.h>
using namespace std;
long long GCD(long long u, long long v) {
  long long r;
  while (v) {
    r = u % v;
    u = v;
    v = r;
  }
  return u;
}
long long modpow(long long a, long long p, long long mod) {
  long long ret = 1;
  while (p) {
    if (p & 1) ret = (ret * a) % mod;
    a = (a * a) % mod;
    p /= 2;
  }
  return ret;
}
long long power(long long a, long long p) {
  long long ret = 1;
  while (p) {
    if (p & 1) ret = (ret * a);
    a = (a * a);
    p /= 2;
  }
  return ret;
}
int a[51];
int main() {
  int i, j, tmp;
  ios_base::sync_with_stdio(0);
  cin.tie(NULL);
  int n, k;
  cin >> n >> k;
  for (i = 0; i < n; i++) cin >> a[i];
  sort(a, a + n);
  if (k > n)
    cout << -1 << endl;
  else
    cout << a[n - k] << " " << a[n - k] << endl;
  return 0;
}
