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#include <bits/stdc++.h>

using namespace std;
int main()
{
	ios_base::sync_with_stdio(false);
	long long n;
	cin >> n;
	int x = 2;
	int tmp;
	for(int i = 0; i < n; i++) {
		cin >> tmp;
		if (tmp == 1 && x > 0)
			x--;
	}
	cout << x << "\n2\n1 2";
	return 0;
}