#include <bits/stdc++.h>

using namespace std;

const int MAX_N = 40000 + 10;

int v[MAX_N];
int init[MAX_N];
int n;

int must;

unsigned int DP[MAX_N][MAX_N / 32];
//DP[i][j] = can we obtain sum i from the first j elements

bool get(int i, int j) {
  return DP[i][j / 32] & (1 << (j % 32));
}

void mset(int i, int j) {
  DP[i][j / 32] |= 1 << (j % 32);
}

int main() {
  cin >> n;
  for(int i = 1; i <= n; ++i) {
    cin >> v[i];
    init[i] = v[i];
    v[i] = v[i] % n;
    if(v[i] == 0) {
      cout << "1\n";
      cout << i << "\n";
      return 0;
    }
  }

  random_shuffle(v + 1, v + n + 1);

  mset(0, 0);

  int s = 0;
  int at = n;

  for(int i = 0; i < n; ++i) {
    for(int j = 1; j <= n; ++j) {
      if(!get(i, j - 1))
        continue;
      int nxt = i + v[j];
      if(nxt >= n)
        nxt -= n;

      mset(i, j);
      mset(nxt, j);

      if(nxt == 0) {
        at = j;
        break;
      }
    }
  }

  assert(get(s, at) == 1);

  vector<int> ans;

  while(at > 0) {
    int prev = s - v[at];
    if(prev < 0)
      prev += n;
    if(get(prev, at - 1)) {
    //we got to (s, at) from (prev, at - 1)
    //so we included v[at]
      ans.push_back(at);
      s = prev;
      --at;

    } else {
    //we did not include v[at]
      --at;
    }
  }

  cout << ans.size() << "\n";
  for(auto i: ans)
    cout << i << " ";
  cout << "\n";

  long long sum = 0;

  for(auto i: ans)
    sum += v[i];

  assert(sum % n == 0);

  return 0;
}