// Programmer:  Rance Cleaveland
// Date:  18 Oct. 2006
//
// Adapted from ArrayExample3 by Fawzi Emad

import java.util.Scanner;

public class Grade {
	
	private static char findGrade(int score) {
		int cutOffs[] = {90, 80, 70, 60};
		char letterGrades[] = {'A', 'B', 'C', 'D'};
		
		for (int i = 0; i < cutOffs.length; i++) {
			if (score >= cutOffs[i])
				return letterGrades[i];
		}
		return 'F';
	}
	
	public static void main(String[] args) {
		int score;
		Scanner sc = new Scanner (System.in);
		for (;;) {
			System.out.print ("Enter score:  ");
			score = sc.nextInt();
			if (score < 0)
				break;
			System.out.println ("Grade is:  " + findGrade(score));
		}
		System.out.println("Good-bye.");
	}
	
}