//SOLUTION CHECKER BROKEN
import java.util.Scanner;

/**
   This program reads a student's final class average,
   and prints out the appropriate letter grade.
*/
public class DoGrades
{
   public static void main(String[] args)
   {
      // Print prompt to enter a final class average
      System.out.println("Enter final class average: ");

      // Read in final class average
      Scanner in = new Scanner(System.in);
      double average = in.nextDouble();

      String finalGrade;

      // Determine and print final grade

      if(average <= 100.0d && average >= 90.0d){finalGrade = "A";}
      else if(average < 90.0d && average >= 80.0d){finalGrade = "B";}
      else if(average < 80.0d && average >= 70.0d){finalGrade = "C";}
      else if(average < 70.0d && average >= 60.0d){finalGrade = "D";}
      else {finalGrade = "F";}

      System.out.println(finalGrade);
   }
}