import java.util.*;

import java.io.*;

public class Enhanced_For
{
	public static void main (String [ ] args) 
	{
	        final String PROMPT = "Please enter a GPA; to quit enter ";

        	final String SENTINEL = "***";

        	final String AVERAGE_MESSAGE = "\n\nThe average GPA is ";

        	LinkedList <Double> gpaList = new LinkedList <Double> ();

        	BufferedReader reader = new BufferedReader (
    						new InputStreamReader (System.in));

        	String line;

        	double sum = 0;

        	try
        	{
        		while (true)
        		{
            			System.out.println (PROMPT + SENTINEL);
            			line = reader.readLine ();
            			if (line.equals (SENTINEL))
                			break;
            			gpaList.add (new Double (line)); // inserts in gpaList
        		} // while
        		for (Double gpa : gpaList)
				sum += gpa;
        		System.out.println (AVERAGE_MESSAGE + (sum / gpaList.size ()));
    	  	} // try
        	catch (IOException e)
	  	{
			System.out.println (e);
	  	} // catch
	}  // method main

} // class Enhanced_For