#include <bits/stdc++.h>
using namespace std;
int main() {
  int k, n;
  int num[60];
  while (2 == scanf("%d%d", &n, &k)) {
    for (int i = 1; i <= n; i++) {
      scanf("%d", &num[i]);
    }
    sort(num + 1, num + n + 1);
    if (n < k)
      printf("-1\n");
    else {
      int c = 0;
      for (int i = n; i >= 1; i--) {
        c++;
        if (c == k) {
          printf("%d %d", num[i], num[i]);
          break;
        }
      }
      printf("\n");
    }
  }
  return 0;
}
