public class Demo
{
    public static void main(String[] args)
    {
        SavingsAccount a = new SavingsAccount(100);
        
        a.withdraw(10); 
        System.out.println(a.getBalance());  // 90
        a.withdraw(10); 
        System.out.println(a.getBalance());  // 80
        a.withdraw(10); 
        System.out.println(a.getBalance());  // 70
        a.withdraw(10); 
        System.out.println(a.getBalance());  // 59 ! ($1 penalty)
    }
}