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#include <bits/stdc++.h>
using namespace std;

int n, res, cnt;

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
	cout.tie(0);
	
	cin >> n;
	for(int i=0; i<n; i++){
		int a;
		cin >> a;
		if(a == 1){
			cnt ++;
		}
	}
	
	if(cnt == 0){
		cout << 2 << "\n";
		
	}
	if(cnt == 1){
		cout << 1 << "\n";
	}
	if(cnt > 1){
		cout << 0 << "\n";
	}
	cout << 2 << "\n";
	cout << 1 << " " << 2 << "\n";
	
	return 0;
}