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

using namespace std;

int main() {
    int n;
    int ones = 0;
    int input;
    cin >> n;
    for(int i = 0; i < n; i++) {
        cin >> input;
        if(input == 1) {
            ones++;
            ones = min(ones, 2);
        }
    }
    cout << 2 - ones << endl;
    cout << 2 << endl;
    cout << 1 << " " << 2 << endl;

    return 0;
}