Definition: In this task, you will use your knowledge about language (and common sense) to determine what element the marked number refers to. The numbers are marked with two underlines around them, like: _ number _. Your answer should be chosen from the given text, and should not contain other words.
Input: Stephen:  Imagine a piano keyboard . Um , 88 keys , only _ 88 _ , and yet , and yet , hundreds of new melodies , new tunes , new harmonies are being composed upon hundreds of different keyboards every day in Dorset alone . Now , our language , Tiger , our language . Hundreds of thousands of available words , frillions of legitimate new ideas ... Hm ? So that I can say the following sentence and be utterly sure that nobody has ever said it before in the history of human communication : " Hold the newsreader 's nose squarely , waiter , or friendly milk will countermand my trousers . "

keys