import java.util.Scanner;

public class Main { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); String grade =scanner.next();

    //write your code here......
    switch(grade){
             case "A":
                System.out.println("优秀");
                break;
            case "B":
                System.out.println("良好");
                break;
            case "C":
                System.out.println("及格");
                break;
            case "D":
                System.out.println("不及格");
                break;
            case "E":
                System.out.println("未知等级");
                break;
            default:
                System.out.println("输入错误");
    }

}

}