import java.io.*;
import java.util.*;
public class Main
{
	public static void main(String args[]) throws Exception
	{
		Scanner cin=new Scanner(System.in);
		int N,i,temp;
		double money[],aver,sum,s1,s2;
		while(true)
		{
			N=cin.nextInt();
			if(N==0) break;
			money=new double[N];
			for(i=0,sum=0,aver=0;i<N;i++)
			{
				money[i]=cin.nextDouble();
				sum+=money[i];
			}
			aver=sum/N;
			temp=(int)(0.5+aver*100);
			aver=temp/100.0;
			for(i=0,s1=0,s2=0;i<N;i++)
			{
				if(money[i]>aver) s1+=money[i]-aver;
				else s2+=aver-money[i];
			}
			sum=(s1<s2)?s1:s2;
			System.out.printf("$%.2f\n",sum);
		}
	}
}