```
public class DeliverySystem {

     public static void main(String[] args) {
        Staff me = new partTimeStaff()
    me.CalcSalary();
    me.CalcBonus();
     }
}

class partTimeStaff extends Staff{
    public void CalcBonus(){..........}
}

class Staff{
        public void CalcSalary() {….........}
}

```

Why is there an error in this code and how do I solve this error ?