interface IQuantityKilo
{
    void DisplayQuantityKilo();
}
interface IQuantityLiter
{
    void DisplayQuantityLiter();
}

abstract class TypeProductsInBag
{
    public abstract void CalculateTypeProductsInBag(int quantity);
}

class FruitsInBag:TypeProductsInBag, IQuantityKilo
{
    public int NumberFruitInBag { get; set; }

    public override void CalculateTypeProductsInBag(int quantity)
    {
        NumberFruitInBag += quantity;
    }

    public void DisplayQuantityKilo()
    {
        //wyświetl ilość kilogramów
    }
}

class DrinksInBag : TypeProductsInBag, IQuantityLiter
{
    public int NumberDrinksInBag { get; set; }

    public override void CalculateTypeProductsInBag(int quantity)
    {
        NumberDrinksInBag += quantity;
    }

    public void DisplayQuantityLiter()
    {
        //wyświetl ilość litrów
    }
}