public class FIFO 
{
	private int[] PSC_Memory;
	private int PSC_PUB_Memory;
	private int PSC_Head,PSC_tail;
	private int flag;			//F=1;E=0;A=-1
	int PSC_Counter;
	
	FIFO(int PUB_Memory)
	{
		PSC_Memory=new int[PUB_Memory];
		PSC_PUB_Memory=PUB_Memory;
		flag=0;
		PSC_Counter=0;
		PSC_Head=0;
		PSC_tail=-1;
	}
	
	private void PSC_insert(int data)
	{
		if(flag==1)
		{
			PSC_remove();
			PSC_insert(data);
		}
		if(flag==0||flag==-1)
		{
			PSC_tail=(PSC_tail+1)%PSC_PUB_Memory;
			PSC_Memory[PSC_tail]=data;
			if(((PSC_tail+1)%PSC_PUB_Memory)==PSC_Head)
			{
				flag=1;
			}
			else
			{
				flag=-1;
			}
		}
	}
	
	private void PSC_remove()
	{
		if(flag==1)
		{
			PSC_Head=(PSC_Head+1)%PSC_PUB_Memory;
		}
		flag=-1;
	}
	
	private boolean PSC_isTarget(int data)
	{
		int target=PSC_Head;
		if(flag!=1&&flag!=0)
		{
			for(;((target+3)%PSC_PUB_Memory)!=PSC_tail;
			target=(target+1)%PSC_PUB_Memory)
			{
				if(PSC_Memory[target]==data)
				{
					return true;
				}
			}
		}
		if(flag==1)
		{
			for(target=0;target<PSC_PUB_Memory;target++)
			{
				if(PSC_Memory[target]==data)
				{
					return true;
				}
			}
		}
		return false;
	}

	public int run(int[] PUB_order,int length)
	{
		int i=0;		//1⁄4orderλ
		for(i=0;i<length;i++)
		{
			if(flag!=0)
			{
				if(PSC_isTarget(PUB_order[i]) )
				{
					PSC_Counter++;
				}
				else
				{
					PSC_insert(PUB_order[i]);
				}
			}
			else
			{
				PSC_insert(PUB_order[i]);
			}
		}
		
		return PSC_Counter;		
	}
}