1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e6 + 6;
vector < int > v;
int n, a;

main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cin >> n;
    for(int i=1; i<=n; i++){
        cin >> a;
        if(a == 1) v.push_back(i);
    }
    if(v.size() >= 2) cout << "0";
    else if(v.size() == 1) cout << "1";
    else cout << "2";
    cout << "\n2\n1 2";
}