class PartyB {
    public static void main(String[] arg) {
        CoffeeCupA c1, c2;
        c1 = new CoffeeCupA();
        c2 = new CoffeeCupA();
        c1.amount = 200;
        c2.amount = 200;
        c1.amount = c1.amount - 20;
    }
}