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

#define mp make_pair
#define ff first
#define ss second
#define eb emplace_back

typedef long long int ll;

inline void readUI(int *i)
{
	register int t=0;
	register char z=getchar_unlocked();
	while (z<'0' && '9'<z)
	{
		z=getchar_unlocked();
	}
	while ('0'<=z && z<='9')
	{
		t=(t<<3)+(t<<1)+z-'0';
		z=getchar_unlocked();
	}
	*i=t;
}

#define debug if(1)

int n, a, ile;

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