static void Main()
{
IBankAccount venusAccount = new SaverAccount();
IBankAccount jupiterAccount = new GoldAccount();
venusAccount.PayIn(200);
venusAccount.Withdraw(100);
WriteLine(venusAccount.ToString());
jupiterAccount.PayIn(500);
jupiterAccount.Withdraw(600);
jupiterAccount.Withdraw(100);
WriteLine(jupiterAccount.ToString());
}