#include <iostream>
using namespace std;

int main() {
	int n;
	cin>>n;
	int a[n+1],odd=0,even;
	for(int i=1;i<=n;++i)
	{
		cin>>a[i];
		if(a[i]==1) odd++;
	}
	even=n-odd;
	if(even>0) 
	{
		cout<<2<<" ";
		even--;
	}
	if(odd>0)
	{
		cout<<1<<" ";
		odd--;
	}
	for(int i=1;i<=even;++i) cout<<2<<" ";
	for(int i=1;i<=odd;++i) cout<<1<<" ";
	return 0;
}