#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 5;
const int MOD = 1e9 + 7;
long long a[N];
int main(void) {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int n;
  cin >> n;
  for (int i = 1; i <= n; i++) cin >> a[i];
  for (long long i = 1; i <= (1 << 11); i++) {
    long long ans1 = 0, ans2 = 0;
    for (int j = 0; j <= 9; j++) {
      if (((i >> j) & 1) == 1)
        ans1 += a[j + 1];
      else
        ans2 += a[j + 1];
    }
    if (ans1 > 0 && ans2 > 0 && ans1 != ans2) {
      vector<long long> t;
      for (int j = 0; j <= 9; j++) {
        if (((i >> j) & 1) == 1) t.push_back(j + 1);
      }
      cout << t.size() << endl;
      for (auto aaa : t) cout << aaa << " ";
      return 0;
    }
  }
  cout << -1;
  return 0;
}
