1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
#include <cstdio>

int main() {
	int n, v, count=0;
	scanf("%d", &n);
	while (n--) {
		scanf("%d", &v);
		if (v == 1) {
			count++;
		}
	}
	printf("%d\n2\n1 2\n", count >= 2 ? 0 : 2-count);
}