import java.util.Scanner;
public class Main {
public static String score(int score) {
if (score >= 90 && score <= 100) {
return "A";
} else if (score >= 60) {
return "B";
} else if (score >= 0) {
return "C";
} else {
return null;
}
}
@SuppressWarnings("resource")
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
int nextInt = in.nextInt();
System.out.println(score(nextInt));
}
}
56
C