In the past, there was a man who kept 30 sheep.
One morning, he discovered that one sheep was missing.
Where had it gone?
Upon investigation, he found that his fold was damaaged.
During the night a wolf had broken into the fold and devoured the sheep.
His friend said to him: "You'd better fix the fold quickly."
He said:" The sheep had already gone, What is the use of fixing the fold."
The following morning, he found that during the night the wolf came again and devoured another sheep.
Not until then did he realize that his friend was right.
He fixed the fold at once, and thereafter no more sheep were taken by the wolf.
