#include <bits/stdc++.h>
using namespace std;
int N;
int main() {
  cin >> N;
  vector<int> v(N), in(N), dc(N);
  for (int i = 0; i < N; ++i) scanf(" %d", &v[i]);
  in = dc = v;
  sort(in.begin(), in.end());
  sort(dc.begin(), dc.end());
  reverse(dc.begin(), dc.end());
  for (int i = 0; i < N; i++) {
    for (int j = i + 1; j < N; j++) {
      if (v[i] == v[j]) continue;
      swap(v[i], v[j]);
      if (v != in && v != dc) return cout << i + 1 << " " << j + 1 << endl, 0;
      swap(v[i], v[j]);
    }
    for (int j = i + 1; j < N; j++) {
      if (v[i + 1] == v[j]) continue;
      swap(v[i + 1], v[j]);
      if (v != in && v != dc) return cout << i + 2 << " " << j + 1 << endl, 0;
      swap(v[i + 1], v[j]);
    }
    while (v[i + 1] == v[i] && i < N) i++;
  }
  puts("-1");
  return 0;
}
