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#include <bits/stdc++.h>
using namespace std;
typedef vector<int> VI;
typedef pair <int,int> ii;
typedef pair <ii,int> iii;
typedef long long LL;
#define pb push_back
const int INF = 2147483647;

int n, a, l;

int main() {
scanf("%d", &n);
l = 0;
while (n--) {
	scanf("%d", &a);
	if (a == 1) l++;
}
l = min(l, 2);
printf("%d\n2\n1 2\n", 2 - l);
return 0;
}