P8671 [Lanqiao Cup 2018 National AC] Josephus Circle.

The $n$ people are numbered $1 \sim n$. If they stand in a circle clockwise in order of their numbers, starting from the person numbered $1$, they count clockwise. (The counting starts from $1$.) When the count reaches $k$, that person leaves the circle. The next person starts counting again from $1$. Find the number of the last remaining person. This is the famous Josephus Circle problem. In this problem, given $n$ and $k$, you need to find the number of the last remaining person.

The input is one line containing two integers $n,k$ separated by spaces.

Output one integer, representing the number of the last remaining person.

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