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#include <stdio.h>

int main()
{
	int n, x, m = 2;

	scanf("%d", &n);
	while (n--) {
		scanf("%d", &x);
		if (x == 1)
			m--;
		if (m <= 0)
			break;
	}

	printf("%d\n2\n1 2\n", m);
	return 0;
}