import java.util.Scanner;

abstract class BaseAlert {
    abstract String generateAlert();
}

class CustomAlert extends BaseAlert {

    @Override
    String generateAlert() {
        return "Custom Alert: Please check your system.";
    }

    String handleAlert(String mode) {
        if (mode.equals("base")) {
            return super.generateAlert(); // fallback to base logic
        } else if (mode.equals("override")) {
            return this.generateAlert(); // normal override
        } else {
            return "Invalid input.";
        }
    }

    // base implementation available using super
    String superGenerateAlert() {
        return "Base Alert: System running normally.";
    }

    @Override
    String generateAlert(String mode) {
        if (mode.equals("base")) {
            return superGenerateAlert();
        } else if (mode.equals("override")) {
            return generateAlert();
        } else {
            return "Invalid input.";
        }
    }
}

public class AbstractAlertSystem {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String mode = sc.nextLine().trim();

        CustomAlert alert = new CustomAlert();
        String output = alert.generateAlert(mode);

        System.out.println(output);
    }
}