#include <bits/stdc++.h>
using namespace std;
int main() {
  std::ios::sync_with_stdio(0);
  cin.tie(NULL);
  cout.tie(NULL);
  int n;
  cin >> n;
  vector<int> v(n);
  for (int i = 0; i < n; i++) cin >> v[i];
  if (n == 1) {
    cout << "-1";
    return 0;
  }
  if (n == 2) {
    if (v[0] == v[1]) {
      cout << "-1";
      return 0;
    }
  }
  vector<int> inx;
  vector<int>::iterator it;
  int sum = 0;
  for (int i = 0; i < n; i++) sum += v[i];
  int i = 0;
  int temp = 0;
  while ((temp + v[i]) == (sum - v[i])) {
    inx.push_back(i + 1);
    temp += v[i];
    sum -= v[i];
    i++;
  }
  if (i == n) {
    cout << "-1";
    return 0;
  }
  if (i == 0) {
    cout << "1\n1";
    return 0;
  }
  it = inx.end() - 1;
  inx.push_back((*it) + 1);
  cout << i + 1 << "\n";
  for (it = inx.begin(); it != inx.end(); it++) cout << (*it) << " ";
  return 0;
}
