#include <bits/stdc++.h>
using namespace std;
struct node {
  int id;
  int value;
};
bool cmp(node a, node b) { return a.value < b.value; }
int main() {
  int n;
  cin >> n;
  node c[n + 1];
  for (int i = 1; i <= n; i++) {
    cin >> c[i].value;
    c[i].id = i;
  }
  if (n == 1 || (n == 2 && c[1].value == c[2].value)) {
    cout << "-1" << endl;
    return 0;
  }
  sort(c + 1, c + n + 1, cmp);
  cout << n - 1 << endl;
  for (int i = 2; i <= n; i++) {
    cout << c[i].id << ' ';
  }
  return 0;
}
