abstract class Citizen {
    private String _name;
    private double _skillLevel;

    public Citizen() {
        _name = "Anajaan the unknown";
        _skillLevel = 0;
    }

    public Citizen(String name, double skillLevel) {
        setName(name);
        setSkillLevel(skillLevel);
    }

    public String getName() {
        return _name;
    }

    public void setName(String name) {
        if (name == null || name.isEmpty())
            System.out.println("Name can’t be null or empty.");
        else
            _name = name;
    }

    public double getSkillLevel() {
        return _skillLevel;
    }

    public void setSkillLevel(double skillLevel) {
        if (skillLevel < 0)
            System.out.println("Skill level can never be less than 0.");
        else
            _skillLevel = skillLevel;
    }

    public abstract double attack();
}

class Paladin extends Citizen {
    private double _affinity;

    public Paladin() {
        super();
        _affinity = 1;
    }

    public Paladin(String name, double skillLevel, double affinity) {
        super(name, skillLevel);
        setAffinity(affinity);
    }

    public double getAffinity() {
        return _affinity;
    }

    public void setAffinity(double affinity) {
        if (affinity < 1)
            System.out.println("Affinity can never be less than 1.");
        else
            _affinity = affinity;
    }

    @Override
    public double attack() {
        if ((int) (Math.random() * 20 + 1) == 1)
            return 0;
        else
            return getSkillLevel() / 2 + _affinity;
    }
}