#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  int ara[n];
  int sum = 0;
  for (int i = int(0); i < int(n); i++) {
    cin >> ara[i];
    sum += ara[i];
  }
  if (n == 1) {
    printf("-1\n");
    return 0;
  }
  set<int> s(ara, ara + n);
  if (n == 2 and s.size() == 1) {
    printf("-1\n");
    return 0;
  }
  int g = 0;
  vector<int> gindex;
  for (int i = 0; i < n; i++) {
    g += ara[i];
    if ((sum - g) == g) {
      gindex.push_back(i + 1);
    } else {
      gindex.push_back(i + 1);
      break;
    }
  }
  if (gindex.size() == 0 or gindex.size() == n) {
    printf("-1\n");
    return 0;
  }
  cout << gindex.size() << endl;
  cout << gindex[0];
  for (int i = 1; i < gindex.size(); i++) {
    cout << " " << gindex[i];
  }
  cout << endl;
}
