#include <bits/stdc++.h>
using namespace std;
int mex(vector<int> a) {
  set<int> b(a.begin(), a.end());
  for (int i = 0;; ++i) {
    if (!b.count(i)) {
      return i;
    }
  }
}
signed main() {
  int n;
  cin >> n;
  vector<pair<int, int> > a(n - 1);
  int c;
  cin >> c;
  int sum = c;
  for (int i = 0; i < n - 1; ++i) {
    cin >> a[i].first;
    a[i].second = i + 2;
    sum += a[i].first;
  }
  int cool = c;
  vector<int> coolici;
  coolici.push_back(1);
  sort(a.begin(), a.end());
  for (int i = 0; i < n - 1; ++i) {
    if (a[i].first * 2 <= c) {
      cool += a[i].first;
      coolici.push_back(a[i].second);
    }
  }
  if (cool * 2 > sum) {
    cout << coolici.size() << endl;
    for (int i = 0; i < coolici.size(); ++i) {
      cout << coolici[i] << ' ';
    }
  } else {
    cout << 0;
  }
}
