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");
}
}
}