#include <bits/stdc++.h>
using namespace std;
int n;
int a[15];
int sum[15];
int main() {
  cin >> n;
  if (n < 2) {
    cout << -1;
    return 0;
  }
  for (int i = 1; i <= n; i++) {
    cin >> a[i];
    sum[i] = sum[i - 1] + a[i];
  }
  int sumall = sum[n];
  for (int i = 1; i <= n; i++) {
    for (int j = 0; j < i; j++) {
      int x = sum[i] - sum[j];
      if (sumall - x == 0) continue;
      if (x != sumall - x) {
        cout << i - j << endl;
        for (int k = j + 1; k <= i; k++) {
          cout << k << " ";
        }
        return 0;
      }
    }
  }
  cout << -1;
  return 0;
}
