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#include <cstdio>

int main() {
	int ones = 0;
	int N;
	
	scanf("%d",&N);
	for (int i=0; i<N; ++i) {
		int d;
		scanf("%d",&d);
		ones += (d==1);
	}

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