// This program asks the user for their percentage in a course
// and prints what letter grade they should receive.

import java.util.*;

public class CourseGrade {
    public static void main(String[] args) {
        Scanner console = new Scanner(System.in);
        System.out.print("Type your percentage: ");
        int percent = console.nextInt();
        
        if (percent >= 90) {
            System.out.println("A");
        } else if (percent >= 80) {
            System.out.println("B");
        } else if (percent >= 70) {
            System.out.println("C");
        } else if (percent >= 60) {
            System.out.println("D");
        } else {
            System.out.println("F");
        }
    }
}