//CS5-HMC-Sp,00-HW10-5
//A. Khakpour, Apr., 00

import java.io.*;
import java.text.*;

class ExamGrades1
{
   //-----------------------------------------------------------------
   //  Computes the average, minimum, and maximum of a set of exam
   //  scores entered by the user.
   //-----------------------------------------------------------------
   public static void main (String[] args) throws IOException
   {
      InputStreamReader a = new InputStreamReader(System.in);
      BufferedReader b = new BufferedReader(a);
      String c;

      int grade, count = 0, sum = 0, max, min;
      double average;

      //  Get the first grade and give min and max that initial value
      System.out.print ("Enter the first grade (-1 to quit): ");
      c = b.readLine();
      grade = Integer.parseInt(c); 

      max = min = grade;

      //  Read and process the rest of the grades
      while (grade >= 0)
      {
         count++;
         sum += grade;

         if (grade > max)
            max = grade;
         else
            if (grade < min)
               min = grade;

         System.out.print ("Enter the next grade (-1 to quit): ");
         c = b.readLine();
         grade = Integer.parseInt(c); 
      }

      //  Produce the final results
      if (count == 0)
         System.out.println ("No valid grades were entered.");
      else
      {
         DecimalFormat fmt = new DecimalFormat ("0.##");
         average = (double)sum / count;
         System.out.println();
         System.out.println ("Total number of students: " + count);
         System.out.println ("Average grade: " + fmt.format(average));
         System.out.println ("Highest grade: " + max);
         System.out.println ("Lowest grade: " + min);
      }
   }
}