1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
#include <iostream>

using namespace std;

int main()
{
    int n, x, ones, ret;
    ones = 0;
    cin >> n;
    for(int i = 0; i < n; i++) {
        cin >> x;
        if (x == 1) ones++;
    }
    if (ones >= 2) ret = 0;
    else ret = 2 - ones;
    cout << ret << endl;
    cout << "2\n1 2";

    return 0;
}