#include <bits/stdc++.h>
int cmp(const void* a, const void* b) {
  return *(long long int*)a > *(long long int*)b ? 1 : -1;
}
int main() {
  int n, k;
  long long int a[52] = {0};
  while (~scanf("%d %d", &n, &k)) {
    for (int i = 0; i < n; i++) scanf("%lld", &a[i]);
    qsort(a, n, sizeof(a[0]), cmp);
    if (k > n)
      printf("-1\n");
    else {
      printf("%lld %lld\n", a[n - k], a[n - k]);
    }
    memset(a, 0, 52);
  }
}
