One day a duck walks into a pharmacy. He asks the clerk, "Do you have any grapes?" The clerk then replies: "No, we don't sell grapes we are a pharmacy. You want the grocery store around the corner." So the duck says "OK" and walks out.

The next day the same duck comes back into the pharmacy and asks "Do you have any grapes?" The clerk replies "No, I said yesterday that you want the grocery store, this is a pharmacy." So the duck again says "OK" and leaves.

The next day the duck comes back in and asks "Got any grapes?"The clerk then gets very angry and says "Look, this is the third day in a row that you have come in asking for grapes. I told you we dont sell grapes! Now if you come back here again asking for grapes I will nail your feet to the floor!!" The duck then says "OK" and leaves.

The fourth day the same duck comes back in the pharmacy and the clerk notices him right away. The duck says "Got any nails?" The clerk is confused and says "No we dont sell nails, we are a pharmacy. You want the hardware store."

So the duck says, "Good. Got any grapes?"