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#include <cstdio>

int main() {

	int N;
	scanf("%d", &N);

	int leafs = 0;
	int degree;
	while (N--)
	{
		scanf("%d", &degree);
		if (degree == 1)
			++leafs;

		if (leafs == 2)
			break;
	}

	printf("%d\n2\n1 2\n", 2 - leafs);

	return 0;
}