Early one morning, Farmer John woke up to the sound of splintering wood. The cows were breaking out of the barn again.
Farmer John had had enough of the morning breakouts, so he nailed a counter to the barn wall. The counter shows how many days have passed since the last breakout. If a breakout happens in the morning, the counter reads 0 that day. If the most recent breakout was 3 days ago, the counter reads 3. Farmer John wrote the counter down every single day.
The year is over and Farmer John wants to settle accounts with the cows, but something about his log looks wrong. He suspects the cows tampered with it. The one thing he is sure of is that he started the log on a day when a breakout happened.
For each possible number of breakouts since the log began, find the smallest number of log entries that must have been tampered with.