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//Daniel Grzegorzewski
#include <bits/stdc++.h>
#pragma GCC optimize("O3")

#define MP make_pair
#define PB push_back
#define ST first
#define ND second

using namespace std;

typedef pair<int, int> PII;
typedef vector<int> VI;
typedef vector<PII> VII;
typedef long long LL;

void init_ios() {
     ios_base::sync_with_stdio(0);
     cin.tie(0);
}

int n, x, jed;

int main() {
  init_ios();
  cin >> n;
  for (int i = 1; i <= n; ++i) {
    cin >> x;
    if (x == 1)
      ++jed;
  }
  if (jed > 1)
    jed = 0;
  else if (jed == 0)
    jed = 2;
  cout<<jed<<"\n2\n1 2\n";
}