#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long int n, k;
  cin >> n;
  vector<pair<long long int, long long int>> v;
  for (int i = 0; i < n; i++) {
    long long int ar;
    cin >> ar;
    v.push_back(make_pair(ar, i + 1));
  }
  if (n == 1) {
    cout << "-1";
    return 0;
  }
  if (n == 2) {
    if (v[0].first == v[1].first) {
      cout << "-1";
      return 0;
    }
  }
  sort(v.begin(), v.end());
  cout << v.size() - 1 << endl;
  for (int i = 1; i < v.size(); i++) cout << v[i].second << " ";
  return 0;
}
