import java.util.Scanner;  // Needed for Input

/**
   This program asks the user to enter a numeric test
   score and displays a letter grade for the score. The
   program displays an error message if an invalid
   numeric score is entered.
*/

public class TestResults
{
   public static void main(String[] args)
   {
      int testScore;    // Numeric test score
      String input;     // To hold the user's input
		Scanner keyboard;

		keyboard = new Scanner(System.in);
		
      // Get the numeric test score.
      testScore = keyboard.nextInt();

      // Display the grade.
      if (testScore < 60)
         System.out.println("Your grade is F.");
      else if (testScore < 70)
         System.out.println("Your grade is D.");
      else if (testScore < 80)
         System.out.println("Your grade is C.");
      else if (testScore < 90)
         System.out.println("Your grade is B.");
      else if (testScore <= 100)
         System.out.println("Your grade is A.");
      else                // Invalid score
         System.out.println("Invalid score.");

   }
}