#include <bits/stdc++.h>
int a[18];
int sum(int i, int n) {
  int j, s = 0;
  for (j = i; j < n; j++) s = s + a[j];
  return s;
}
void print(int n) {
  int i;
  printf("%d\n", n);
  for (i = 1; i <= n; i++) printf("%d ", i);
}
int main() {
  int n, i, sum1 = 0, sum2 = 0;
  scanf("%d", &n);
  for (i = 0; i < n; i++) scanf("%d", &a[i]);
  if (n == 1) {
    printf("-1");
    return 0;
  } else if (n == 2) {
    if (a[0] == a[1])
      printf("-1");
    else
      printf("1\n1");
    return 0;
  } else {
    for (i = 1; i < n; i++) {
      sum2 = sum(0, i);
      sum1 = sum(i, n);
      if (sum1 != sum2) {
        print(i);
        return 0;
      }
    }
  }
  return 0;
}
