1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
#include <iostream>
using namespace std;

int main()
{
  iostream::sync_with_stdio(false);
  cin.tie(nullptr);

  int n;
  cin >> n;

  int cnt1 = 0;
  for (int i = 0; i < n; ++i) {
    int x;
    cin >> x;
    if (x == 1) ++cnt1;
  }

  cout << max(0, 2 - cnt1);
  cout << "\n2\n1 2\n";

  return 0;
}