#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n;
  while (scanf("%lld", &n) == 1) {
    long long ara[n + 1];
    for (long long i = 0; i < n; i++) {
      scanf("%lld", ara + i);
      if (i == 0) continue;
      ara[i] += ara[i - 1];
    }
    for (long long i = n - 1; i >= 0; i--) {
      if ((ara[n - 1] - ara[i - 1]) != ara[i - 1]) {
        if (i == 0) {
          printf("-1\n");
          break;
        }
        printf("%lld\n", i);
        for (long long k = 1; k <= i; k++) printf("%lld ", k);
        printf("\n");
        break;
      }
    }
  }
  return 0;
}
