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......
//采用字符串比较
// if(grade.equals("A")){ // System.out.print("优秀"); // }else if(grade.equals("B")){ // System.out.print("良好"); // }else if(grade.equals("C")){ // System.out.print("及格"); // }else if(grade.equals("D")){ // System.out.print("不及格"); // }else{ // System.out.print("未知等级"); // }
//采用字符比较
char cha = grade.charAt(0);
if(cha == 'A'){
System.out.print("优秀");
}else if(cha == 'B'){
System.out.print("良好");
}else if(cha == 'C'){
System.out.print("及格");
}else if(cha == 'D'){
System.out.print("不及格");
}else{
System.out.print("未知等级");
}
}
}