One day a rich man meets Sam. The rich man asks, "I hear you're very clever and nothing is difficult to you. Can you tell me why you are so clever?" Sam answers with a smile, "Oh, I am not clever. Instead   , you are too foolish ." The rich man becomes very angry. Sam says, "Please don't be angry. If you don't believe  me, now let me ask you a question. If you put together one group of sheep and another group of sheep, how many groups of sheep do you have?" "Why! That's an easy question. One and one is two, and anybody knows that. I have two groups of sheep." Sam laughs and says, "You are wrong. When two groups of sheep are put together, there is still one group. That's the easiest question in the world." The rich man becomes angry because  _  .
Sam is foolish Sam says he is foolish Sam is clever Sam isn't clever