import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner sc=new Scanner(System.in);
int score=sc.nextInt();
if(score<60)System.out.println("不及格");
else {
if (score < 70 && score >60) System.out.println("及格");
else {
if(score<80&&score>=70)System.out.println("中");
else {
if(score<90&&score>=80)System.out.println("良");
else {
if(score<=100&&score>=90)System.out.println("优");
}
}
}
}
sc.close();
}
}