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#include <cstdio>

using namespace std;

int main() {
	int n,x;
	scanf("%d", &n);
	int count1 = 0;
	for(int i=0;i<n;++i) {
		scanf("%d", &x);
		if(x==1)
			++count1;
	}
	printf("%d\n2\n1 2", (count1>=2?0:2-count1));
	return 0;
}