#include<stdio.h>

int n,tmp,a[4],b[4];

int max(int a,int b)
{
	return a>b?a:b;
}

int main()
{
	freopen("egroup.in","r",stdin);
	freopen("egroup.out","w",stdout);
	int i;
	scanf("%d",&n);
	for(i=1;i<=n;i++)
	{
		scanf("%d",&tmp);
		if(tmp==1)
		{
			a[1]++;
			b[1]=max(max(b[1],b[2]),b[3])+1;
		}
		else if(tmp==2)
		{
			a[2]=max(a[1],a[2])+1;
			b[2]=max(b[2],b[3])+1;
		}
		else
		{
			a[3]=max(max(a[1],a[2]),a[3]);
			b[3]++;
		}
	}
	printf("%d\n",n-max(max(max(a[1],a[2]),a[3]),max(max(b[1],b[2]),b[3])));
	return 0;
}