> import java.io.*;
> import java.util.*;
> import java.math.*;
> import java.text.*;
> public class Main1004{
> 	static Scanner cin=new Scanner(System.in);
> 	static public PrintWriter cout=new PrintWriter(System.out,true);
> 	public static void main(String[]args)
> 	{
> 		double sum=0;
> 		double average=0;
> 		for(int i=0;i<12;i++)
> 		{
> 			sum+=cin.nextDouble();
> 		}
> 		average=sum/12;
> 		DecimalFormat df=new DecimalFormat("0.00");
> 		cout.println("$"+df.format(average));
> 	}
> }