A 9-year-old boy and a 4-year-old boy walked into a grocery store. The 9-year-old boy took a pack of sanitary napkins from the shelf and came to the counter to pay the bill.

The waiter asked: "Do you want to buy it for your mother? Child", "No", the boy replied.

"Then you must buy it for your sister!" "No," the boy said. The waiter was confused: "Not for your mother, nor for your sister, who are you going to buy it for?"

"I want it for my 4-year-old brother," the boy said, "Watch it on TV , using this thing, I can ride a bicycle and swim, but my brother can't do either of them.