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#include <cstdio>
#include <cassert>
#include <set>
#include <algorithm>
#include <cstring>

const int M = 201013;

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