1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
#include <iostream>
#include "bits/stdc++.h"
using namespace std;

int n;
int a;

int main() {
    ios_base::sync_with_stdio(0);

    int numberOfOnes = 0;

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

    if(numberOfOnes >= 2) {
        cout << 0 << endl;
    } else if(numberOfOnes == 1) {
        cout << 1 << endl;
    } else {
        cout << 2 << endl;
    }
    cout << 2 << endl;
    cout << "1 2" << endl;

    return 0;
}