Need a little clarification with Monkey Typing

In the explanation it states, "If a word appears several times in the text, it should be counted only once."

In the example, line 2: count_words("Bananas, give me bananas!!!", {"banana", "bananas"}) == 2

The word "bananas" is counted more than once. So should each occurrence be counted as in the example? Or only the first occurrence as in the explanation?

Thank you