namespace Accounting
{
    public class BankAccount
    {
        // Define the Account class members here...
    }

    public class SavingsAccount : BankAccount
    {
        // Define the SavingsAccount class members here...
    }

    public class CurrentAccount : BankAccount
    {
        // Define the CurrentAccount class members here...
    }

    public class OverdraftFacility : BankAccount
    {
        // Define the OverdraftFacility class members here...
    }
}