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() {
    ios::sync_with_stdio(0);

    int n;
    cin >> n;

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

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

    return 0;
}