1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
#include<bits/stdc++.h>
using namespace std;

int main(void){
	ios_base::sync_with_stdio(false);

	int n;
	cin >> n;
	int x=2;

	for(int i=0;i<n;i++){
		int a;
		cin >> a;
		x -= (a == 1 ? 1 : 0);
	}

	x=max(0,x);
	cout << x << "\n";
	cout << 2 << "\n";
	cout << 1 << " " << 2 << "\n";

	return 0;
}