#include <bits/stdc++.h>
using namespace std;
const int INF = 0x3f3f3f3f;
const long long LL_INF = 0x3f3f3f3f3f3f3f3f;
const int maxn = 100000 + 10;
const int mod = 1e9 + 7;
int a[maxn];
int main() {
  int n, sum = 0;
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    scanf("%d", &a[i]);
    sum += a[i];
  }
  int flag = -1;
  if (n == 1) {
    printf("-1\n");
    return 0;
  } else {
    int cnt = 0;
    for (int i = 0; i < n - 1; i++) {
      cnt += a[i];
      if (sum - cnt != cnt) {
        flag = i;
        break;
      }
    }
  }
  if (flag == -1) {
    printf("-1\n");
    return 0;
  } else {
    printf("%d\n", flag + 1);
    for (int i = 1; i <= flag + 1; i++) printf("%d%c", i, " \n"[i == flag + 1]);
  }
}
