// Στρατηγική 1η: Πιστωτική Κάρτα
class CreditCardStrategy implements PaymentStrategy {
    private String name;
    private String cardNumber;

    public CreditCardStrategy(String name, String cardNumber) {
        this.name = name;
        this.cardNumber = cardNumber;
    }

    @Override
    public void pay(double amount) {
        System.out.println("Πληρωμή " + amount + "€ με Πιστωτική Κάρτα (Κάτοχος: " + name + ").");
    }
}

// Στρατηγική 2η: PayPal
class PayPalStrategy implements PaymentStrategy {
    private String email;

    public PayPalStrategy(String email) {
        this.email = email;
    }

    @Override
    public void pay(double amount) {
        System.out.println("Πληρωμή " + amount + "€ μέσω PayPal (Email: " + email + ").");
    }
}