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#include <bits/stdc++.h>
using namespace std;
const int MAXN = 2e5+69;
int c1, n;
int main() {
	scanf("%d", &n);
	while (n--) {
		int tmp;
		scanf("%d", &tmp);
		if (tmp == 1)
			c1++;
	}
	printf("%d\n2\n1 2\n", 2-min(c1,2));
}