#include <bits/stdc++.h>
using namespace std;
int N;
int main() {
  srand(time(0));
  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 < 1000; i++) {
    int L = rand() % N;
    int R = rand() % N;
    if (v[L] == v[R]) continue;
    swap(v[L], v[R]);
    if (v != in && v != dc)
      return cout << min(L, R) + 1 << " " << max(L, R) + 1 << endl, 0;
    swap(v[L], v[R]);
  }
  if (N > 2)
    for (int i = 1; i < N; i++) {
      int L = 0;
      int R = i;
      if (v[L] == v[R]) continue;
      swap(v[L], v[R]);
      if (v != in && v != dc)
        return cout << min(L, R) + 1 << " " << max(L, R) + 1 << endl, 0;
      swap(v[L], v[R]);
    }
  if (N > 2)
    for (int i = 2; i < N; i++) {
      int L = 1;
      int R = i;
      if (v[L] == v[R]) continue;
      swap(v[L], v[R]);
      if (v != in && v != dc)
        return cout << min(L, R) + 1 << " " << max(L, R) + 1 << endl, 0;
      swap(v[L], v[R]);
    }
  puts("-1");
  return 0;
}
