#include <iostream>
#include <algorithm>
#include <vector>

using namespace std;

int main() {
  // Bemenet olvasása
  int n;
  cin >> n;

  vector<int> a(n);
  for (int i = 0; i < n; i++) {
    cin >> a[i];
  }

  // Keresés a maximális távolságú inverzióra
  int max_distance = 0;
  pair<int, int> max_inversion;
  vector<int> sorted(a);
  sort(sorted.begin(), sorted.end());
  for (int i = 0; i < n; i++) {
    int j = lower_bound(sorted.begin(), sorted.end(), a[i]) - sorted.begin();
    int distance = n - j - 1;
    if (distance > max_distance) {
      max_distance = distance;
      max_inversion = {i, n-1};
    }
  }

  // Kimenet írása
  if (max_distance == 0) {
    cout << -1 << endl;
  } else {
    cout << max_inversion.first+1 << " " << max_inversion.second+1 << endl;
  }

  return 0;
}