A farmer comes home to find his sheepdog waiting for him.
The sheepdog says: “I herded the sheep into the barn, just like you asked! “You sure you got them all? ”The farmer replies. “Yep! All 40 of them!” Says the sheepdog. “40? But I only have 37 sheep.” Replies the farmer. The sheepdog answers: “I know. I rounded them up for you.”