import java.until.Scanner;
class Test1_If{
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("请输入学生成绩范围在0到100之间");
int x = sc.nextInt();
if (x >=90 && x <=100) {
System.out.println("优");
}else if (x >= 80 && x <= 89) {
System.out.println("良");
}else if (x >= 70 && x <= 79) {
System.out.println("中");
}else if (x >= 60 && x <= 69) {
System.out.println("及");
}else if (x >= 0 && x <= 59) {
System.out.println("差");
}else {
System.out.println("成绩录入错误");
}
}
}