#include <bits/stdc++.h>
using namespace std;
int cnt = 0;
int main() {
  int N, b[10];
  cin >> N;
  for (int i = 0; i < N; i++) cin >> b[i];
  for (int i = 0; i < (1 << N); i++) {
    int g = 0, a = 0;
    for (int j = 0; j < N; j++)
      if (i & (1 << j))
        g += b[j];
      else
        a += b[j];
    if (g > 0 && a > 0 && a != g) {
      vector<int> v;
      for (int j = 0; j < N; j++)
        if (i & (1 << j)) v.push_back(j + 1);
      cout << v.size() << endl;
      for (auto e : v) cout << e << " ";
      return 0;
    }
  }
  cout << -1;
}
