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

using namespace std;

int n;

int main() {
	cin >> n;

	int cnt = 0;
	while (n--) {
		int a;
		cin >> a;

		if (a == 1)
			++cnt;
	}

	printf("%d\n2\n1 2\n", max(2 - cnt, 0));
}