The king returns
A king has \(K\) servants. He ordered them to stand in a circle and numbered them from 1 to \(K\).
He gave to number 1 a sword and ordered him to kill the one next in number and pass the sword until only one left.
(1 kills 2 and passes to 3 and so on)
how many servants the king need to make the \(K\) numbered servant to stay last?
Note: \(K\) can be 1 but not 0
Take \(N\) as a positive integer.