#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, ar[1007], k, a = 0, b = 0;
  scanf("%d", &n);
  for (int i = 0; i < n; ++i) {
    scanf("%d", &ar[i]);
    a += ar[i];
  }
  if (n == 1) {
    printf("-1\n");
    return 0;
  }
  int f = 0;
  for (int i = 0; i < n; ++i) {
    b = ar[i];
    int x = a - ar[i];
    if (b == x) {
    } else {
      ar[i] = 0;
      f = 1;
      break;
    }
  }
  if (f == 0) {
    printf("-1\n");
    return 0;
  }
  printf("%d\n", n - 1);
  for (int i = 0; i < n; ++i) {
    if (ar[i] != 0) {
      printf("%d ", i + 1);
    }
  }
}
