import java.util.*;

public class Score2Grade {
    public static void main(String[] args) {

        int score, number;
        char grade;

        Scanner sc = new Scanner(System.in);
        System.out.print("성적을 입력하시오: ");
        score = sc.nextInt();
        number = score / 10;
        switch (number) {
            case 10:
            case 9:			grade = 'A';			break;
            case 8:			grade = 'B';			break;
            case 7:			grade = 'C';			break;
            case 6:			grade = 'D';			break;
            default:			grade = 'F';			break;
        }
        System.out.print("학점: " + grade);
    }
}
