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