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#include<cstdio>

int n, x, ile1;

int main() {
	scanf("%d", &n);

	for(int i=0;i<n;i++) {
		scanf("%d", &x);
		if(x == 1)ile1++;
	}

	printf("%d\n2\n1 2\n", ile1>=2 ? 0 : (2 - ile1));
	return 0;
}