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#include <bits/stdc++.h>

using namespace std;

long long n,a,j=0;

int main() {
	scanf("%lld",&n);
	for (long long i=0; i<n; ++i) {
		scanf("%lld",&a);
		if (a==1) {++j;}
	}
	printf("%lld\n2\n1 2\n",2-min(j,(long long)2));
	return 0;
}