#include <bits/stdc++.h>
long long poww(long long x, long long y) {
  long long res = 1;
  x %= 1000000007;
  for (; y; y >>= 1) {
    if (y & 1) res = res * x % 1000000007;
    x = x * x % 1000000007;
  }
  return res;
}
using namespace std;
int a[15], n;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  int i, j, k = 10000;
  cin >> n;
  for (i = 0; i < n; ++i) {
    cin >> a[i];
    if (k > a[i]) {
      k = a[i];
      j = i + 1;
    }
  }
  if (n == 1)
    cout << -1;
  else if (n == 2) {
    if (a[0] == a[1])
      cout << -1;
    else
      cout << 1 << '\n' << j;
  } else
    cout << 1 << '\n' << j;
  return 0;
}
