#include <bits/stdc++.h>
using namespace std;
int n, a[100005];
inline bool isX() {
  for (int i = 2; i <= n; i++)
    if (a[i - 1] > a[i]) return false;
  return true;
}
inline bool isN() {
  for (int i = 2; i <= n; i++)
    if (a[i - 1] < a[i]) return false;
  return true;
}
inline bool check() { return isX() || isN(); }
inline bool One_Val() {
  for (int i = 2; i <= n; i++)
    if (a[i] != a[i - 1]) return false;
  return true;
}
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) scanf("%d", a + i);
  if (One_Val()) {
    printf("-1");
    return 0;
  }
  for (int i = 1; i <= n; i++)
    for (int j = i + 1; j <= n; j++)
      if (a[i] != a[j]) {
        swap(a[i], a[j]);
        if (!check()) {
          printf("%d %d\n", i, j);
          return 0;
        }
        swap(a[i], a[j]);
      }
  printf("-1");
  return 0;
}
