Alice works in a chemists on Saturdays with her dad who is the pharmacist. One weekend, her dad decides to have the morning off and to leave Alice to mind the shop.

Now, pay attention, he says. Under the counter are two piles of brown paper bags with condoms in them. If a man comes in and asks for a £1 bag, give him one of the small left-hand bags. If a man comes in and asks for a £1.75 bag, give him one of the bigger right-hand bags. Got that?

Alice nods and dad goes home for a nap.

During the morning, Alice is doing a roaring trade in £1 and £1.75 bags. Nearing lunchtime, an enormous 66 black man walks into the shop.

Can I help you? asks Alice.

Yes, give me £3.50 please demands the man.

Alice looks the man up and down, looks at the piles of bags and dashes
into the back of the shop to phone her dad.

What is it? he asks. Have you sold all the bags?

No!! cries Alice. Theres this man in there asking for £3.50!

Ah, says the chemist knowingly. Is he a huge black man, about 66 tall?

Yes!! shrieks Alice, nearly hysterical.

Give him the bloody money then girl, hes the windowcleaner.