import java.util.Scanner;
public class Ex2
{
    static Scanner reader=new Scanner(System.in);
    public static double avg()
    {
        double grade,avg,sum=0;
        int counter=0;
        System.out.println("Type a grade");
        grade=reader.nextDouble();
        if (grade==0)
            return 0;
        while (grade!=-1)
        {
            counter++;
            sum=sum+grade;
            System.out.println("Type a grade");
            grade=reader.nextDouble();
        }
        avg=sum/counter;
        return avg;
    }
    public static void main(String[]args)
    {
        double avg,best=0;
        System.out.println("Type student ID");
        String ID=reader.next();
        if(ID.equals("0000")==false)
        {
            avg=avg();
            best=avg;
            System.out.println("Type student ID");
            ID=reader.next();
        }
        while(ID.equals("0000")==false)
        {
            avg=avg();
            if (avg>best)

            {
                best=avg;
            }
            System.out.println("Type student ID");
            ID=reader.next();
        }
        System.out.println("The best avg is:" + best);
    }
}