class PartyD {
    public static void main(String[] arg) {
        CoffeeCupD.setRatio(1.0F - 0.2F);
        CoffeeCupD c1 = new CoffeeCupD(), c2 = new CoffeeCupD();
        c1.amount = c2.amount 
                  = (int) (CoffeeCupD.ratio * CoffeeCupD.volume);
        c1.amount -= 20;
    }
}