"Lie" joke

Two boys were arguing when the teacher entered the room.
The teacher says, "Why are you arguing?"

One boy answers, "We found a ten dollor bill and
decided to give it to whoever tells the biggest lie."

"You should be ashamed of yourselves," said the
teacher,

"When I was your age I didn`t even know what
a lie was."

The boys gave the ten dollars to the teacher.