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#include<iostream>
#include<algorithm>
#include<vector>
using namespace std;

int main()
{
	int n;
	cin >> n;
	vector<int>deg(n);
	for (int i = 0; i < n; ++i) cin >> deg[i];
	sort(deg.begin(), deg.end());
	int res = 2;
	if (deg[0] == 1)
	{
		--res;
		if (deg[1] == 1)
			--res;
	}
	cout << res << "\n2\n1 2";
	return 0;
}