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......
char temp = grade.charAt(0);//此题不能直接将grade与A、B、C、D进行比较,需要转化为char类型进行比较。此函数调用即是为了转为char类型
//此题用swtich方法更加巧妙简便,我提供一个if、elseif的方法供大家参考
if(temp == 'A'){
System.out.print("优秀");
}
else if(temp == 'B'){
System.out.print("良好");
}
else if(temp == 'C'){
System.out.print("及格");
}
else if(temp == 'D'){
System.out.print("不及格");
}
else{
System.out.print("未知等级");
}
}
}